diff --git a/app/controllers/administrateurs/archives_controller.rb b/app/controllers/administrateurs/archives_controller.rb
index e93015927..2fdd834f3 100644
--- a/app/controllers/administrateurs/archives_controller.rb
+++ b/app/controllers/administrateurs/archives_controller.rb
@@ -8,7 +8,7 @@ module Administrateurs
     def index
       @exports = Export.find_for_groupe_instructeurs(all_groupe_instructeurs.map(&:id), nil)
       @average_dossier_weight = @procedure.average_dossier_weight
-      @count_dossiers_termines_by_month = Traitement.count_dossiers_termines_by_month(all_groupe_instructeurs)
+      @count_dossiers_termines_by_month = @procedure.dossiers.processed_by_month(all_groupe_instructeurs).count
       @archives = Archive.for_groupe_instructeur(all_groupe_instructeurs).to_a
     end
 
diff --git a/app/controllers/instructeurs/archives_controller.rb b/app/controllers/instructeurs/archives_controller.rb
index e059c5cd4..44e6d71fc 100644
--- a/app/controllers/instructeurs/archives_controller.rb
+++ b/app/controllers/instructeurs/archives_controller.rb
@@ -7,7 +7,7 @@ module Instructeurs
 
     def index
       @average_dossier_weight = @procedure.average_dossier_weight
-      @count_dossiers_termines_by_month = Traitement.count_dossiers_termines_by_month(groupe_instructeurs)
+      @count_dossiers_termines_by_month = @procedure.dossiers.processed_by_month(groupe_instructeurs).count
       @archives = Archive.for_groupe_instructeur(groupe_instructeurs).to_a
     end
 
diff --git a/app/models/dossier.rb b/app/models/dossier.rb
index 477e10c15..579624d4c 100644
--- a/app/models/dossier.rb
+++ b/app/models/dossier.rb
@@ -235,11 +235,16 @@ class Dossier < ApplicationRecord
   scope :en_instruction,              -> { not_archived.state_en_instruction }
   scope :termine,                     -> { not_archived.state_termine }
 
+  scope :processed_by_month, -> (all_groupe_instructeurs) {
+    state_termine
+      .where(groupe_instructeurs: all_groupe_instructeurs)
+      .group_by_period(:month, :processed_at, reverse: true)
+  }
+
   scope :processed_in_month, -> (date) do
     date = date.to_datetime
     state_termine
-      .joins(:traitements)
-      .where(traitements: { processed_at: date.beginning_of_month..date.end_of_month })
+      .where(processed_at: date.beginning_of_month..date.end_of_month)
   end
   scope :ordered_for_export, -> {
     order(depose_at: 'asc')
diff --git a/app/models/traitement.rb b/app/models/traitement.rb
index 4975bbcc1..a4f882810 100644
--- a/app/models/traitement.rb
+++ b/app/models/traitement.rb
@@ -25,30 +25,4 @@ class Traitement < ApplicationRecord
       .where.not('dossiers.depose_at' => nil, processed_at: nil)
       .order(:processed_at)
   end
-
-  scope :termine_close_to_expiration, -> do
-    joins(dossier: :procedure)
-      .termine
-      .where(process_expired: true)
-      .where('dossiers.state' => Dossier::TERMINE)
-      .where("traitements.processed_at + (procedures.duree_conservation_dossiers_dans_ds * INTERVAL '1 month') - INTERVAL :expires_in < :now", { now: Time.zone.now, expires_in: Dossier::INTERVAL_BEFORE_EXPIRATION })
-  end
-
-  def self.count_dossiers_termines_by_month(groupe_instructeurs)
-    last_traitements_per_dossier = Traitement
-      .select('max(traitements.processed_at) as processed_at')
-      .termine
-      .where(dossier: Dossier.state_termine.where(groupe_instructeur: groupe_instructeurs))
-      .group(:dossier_id)
-      .to_sql
-
-    sql = <<~EOF
-      select date_trunc('month', r1.processed_at::TIMESTAMPTZ AT TIME ZONE '#{Time.zone.formatted_offset}'::INTERVAL) as month, count(r1.processed_at)
-      from (#{last_traitements_per_dossier}) as r1
-      group by date_trunc('month', r1.processed_at::TIMESTAMPTZ AT TIME ZONE '#{Time.zone.formatted_offset}'::INTERVAL)
-      order by month desc
-    EOF
-
-    ActiveRecord::Base.connection.execute(sql)
-  end
 end
diff --git a/app/views/shared/archives/_table.html.haml b/app/views/shared/archives/_table.html.haml
index 178b0c407..f63d6aa8d 100644
--- a/app/views/shared/archives/_table.html.haml
+++ b/app/views/shared/archives/_table.html.haml
@@ -7,17 +7,15 @@
       %th.center Télécharger
 
   %tbody
-  - count_dossiers_termines_by_month.each do |count_by_month|
-    - month = count_by_month["month"].to_date
-    - nb_dossiers_termines = count_by_month["count"]
-    - matching_archive = archives.find { |archive| archive.time_span_type == 'monthly' && archive.month == month }
-    - weight = estimate_weight(matching_archive, nb_dossiers_termines, average_dossier_weight)
+  - count_dossiers_termines_by_month.each do |date, count|
+    - matching_archive = archives.find { |archive| archive.time_span_type == 'monthly' && archive.month == date.month }
+    - weight = estimate_weight(matching_archive, count, average_dossier_weight)
 
     %tr
       %td
-        = I18n.l(month, format: "%B %Y").capitalize
+        = I18n.l(date, format: "%B %Y").capitalize
       %td.text-right
-        = nb_dossiers_termines
+        = count
       %td.text-right
         = number_to_human_size(weight)
       %td.center
@@ -30,7 +28,7 @@
             %span.icon.retry
             = t(:archive_pending_html, scope: [:instructeurs, :procedure], created_period: time_ago_in_words(matching_archive.created_at))
         - elsif weight.nil? || weight < Archive::MAX_SIZE
-          = link_to create_archive_url(procedure, month), method: :post, class: "button" do
+          = link_to create_archive_url(procedure, date), method: :post, class: "button" do
             %span.icon.new-folder
             Demander la création
         - else
diff --git a/spec/models/dossier_spec.rb b/spec/models/dossier_spec.rb
index beeac792e..30d468ca6 100644
--- a/spec/models/dossier_spec.rb
+++ b/spec/models/dossier_spec.rb
@@ -1709,4 +1709,50 @@ describe Dossier do
       end
     end
   end
+
+  describe '#processed_by_month' do
+    let(:procedure) { create(:procedure, :published, groupe_instructeurs: [groupe_instructeurs]) }
+    let(:groupe_instructeurs) { create(:groupe_instructeur) }
+
+    before do
+      create_dossier_for_month(procedure, 2021, 3)
+      create_dossier_for_month(procedure, 2021, 3)
+      create_archived_dossier_for_month(procedure, 2021, 3)
+      create_dossier_for_month(procedure, 2021, 2)
+    end
+
+    subject do
+      Timecop.freeze(Time.zone.local(2021, 3, 5)) do
+        Dossier.processed_by_month(groupe_instructeurs).count
+      end
+    end
+
+    it 'count dossiers_termines by month' do
+      expect(count_for_month(subject, 3)).to eq 3
+      expect(count_for_month(subject, 2)).to eq 1
+    end
+
+    it 'returns descending order by month' do
+      expect(subject.keys.first.month).to eq 3
+      expect(subject.keys.last.month).to eq 2
+    end
+  end
+
+  private
+
+  def count_for_month(processed_by_month, month)
+    processed_by_month.find { |date, _count| date.month == month }[1]
+  end
+
+  def create_dossier_for_month(procedure, year, month)
+    Timecop.freeze(Time.zone.local(year, month, 5)) do
+      create(:dossier, :accepte, :with_attestation, procedure: procedure)
+    end
+  end
+
+  def create_archived_dossier_for_month(procedure, year, month)
+    Timecop.freeze(Time.zone.local(year, month, 5)) do
+      create(:dossier, :accepte, :archived, :with_attestation, procedure: procedure)
+    end
+  end
 end
diff --git a/spec/models/traitement_spec.rb b/spec/models/traitement_spec.rb
deleted file mode 100644
index d84bdeedc..000000000
--- a/spec/models/traitement_spec.rb
+++ /dev/null
@@ -1,49 +0,0 @@
-describe Traitement do
-  describe '#count_dossiers_termines_by_month' do
-    let(:procedure) { create(:procedure, :published, groupe_instructeurs: [groupe_instructeurs]) }
-    let(:groupe_instructeurs) { create(:groupe_instructeur) }
-
-    before do
-      create_dossier_for_month(procedure, 2021, 3)
-      create_dossier_for_month(procedure, 2021, 3)
-      create_archived_dossier_for_month(procedure, 2021, 3)
-      create_dossier_for_month(procedure, 2021, 2)
-    end
-
-    subject do
-      Timecop.freeze(Time.zone.local(2021, 3, 5)) do
-        Traitement.count_dossiers_termines_by_month(groupe_instructeurs)
-      end
-    end
-
-    it 'count dossiers_termines by month' do
-      expect(count_for_month(subject, 3)).to eq 3
-      expect(count_for_month(subject, 2)).to eq 1
-    end
-
-    it 'returns descending order by month' do
-      expect(subject[0]["month"].to_date.month).to eq 3
-      expect(subject[1]["month"].to_date.month).to eq 2
-    end
-  end
-
-  private
-
-  def count_for_month(count_dossiers_termines_by_month, month)
-    count_dossiers_termines_by_month.find do |count_by_month|
-      count_by_month["month"].to_date.month == month
-    end["count"]
-  end
-
-  def create_dossier_for_month(procedure, year, month)
-    Timecop.freeze(Time.zone.local(year, month, 5)) do
-      create(:dossier, :accepte, :with_attestation, procedure: procedure)
-    end
-  end
-
-  def create_archived_dossier_for_month(procedure, year, month)
-    Timecop.freeze(Time.zone.local(year, month, 5)) do
-      create(:dossier, :accepte, :archived, :with_attestation, procedure: procedure)
-    end
-  end
-end
diff --git a/spec/views/shared/archives/_table.html.haml_spec.rb b/spec/views/shared/archives/_table.html.haml_spec.rb
index 688e3a760..298603b34 100644
--- a/spec/views/shared/archives/_table.html.haml_spec.rb
+++ b/spec/views/shared/archives/_table.html.haml_spec.rb
@@ -3,21 +3,21 @@ RSpec.describe 'shared/archives/_table.html.haml', type: :view do
 
   let(:procedure) { create(:procedure) }
   let(:all_archives) { create_list(:archive, 2) }
-  let(:month_date) { "2022-01-01T00:00:00+00:00" }
+  let(:month_date) { DateTime.parse("2022-01-01T00:00:00+00:00") }
   let(:average_dossier_weight) { 1024 }
 
   before do
       allow(view).to receive(:create_archive_url).and_return("/archive/created/stubed")
     end
 
-  subject { render 'shared/archives/table.html.haml', count_dossiers_termines_by_month: [{ "month" => month_date, "count" => 5 }], archives: all_archives + [monthly_archive].compact, average_dossier_weight: average_dossier_weight, procedure: procedure }
+  subject { render 'shared/archives/table.html.haml', count_dossiers_termines_by_month: { month_date => 5 }, archives: all_archives + [monthly_archive].compact, average_dossier_weight: average_dossier_weight, procedure: procedure }
 
   context "when archive is available" do
     let(:monthly_archive) { create(:archive, time_span_type: "monthly", month: month_date, job_status: :generated, file: Rack::Test::UploadedFile.new('spec/fixtures/files/RIB.pdf', 'application/pdf')) }
     it 'renders archive by month with estimate_weight' do
       expect(subject).to have_text("Janvier 2022")
       expect(subject).to have_text("Télécharger")
-      expect(subject).to have_text("338 ko")
+      expect(subject).to have_text("5 ko")
     end
   end