diff --git a/app/models/concerns/procedure_stats_concern.rb b/app/models/concerns/procedure_stats_concern.rb
index cfffaaa8c..307982075 100644
--- a/app/models/concerns/procedure_stats_concern.rb
+++ b/app/models/concerns/procedure_stats_concern.rb
@@ -83,14 +83,18 @@ module ProcedureStatsConcern
 
   def usual_traitement_time_for_recent_dossiers(nb_days)
     now = Time.zone.now
+    clusters_count = 3
+
     traitement_time =
       traitement_times((now - nb_days.days)..now)
         .map { |times| times[:processed_at] - times[:depose_at] }
-        .percentile(USUAL_TRAITEMENT_TIME_PERCENTILE)
-        .ceil
-
-    traitement_time = nil if traitement_time == 0
-    traitement_time
+        .sort
+    if traitement_time.size >= clusters_count
+      traitement_time.each_slice((traitement_time.size.to_f / clusters_count.to_f).ceil)
+        .map { _1.percentile(USUAL_TRAITEMENT_TIME_PERCENTILE) }
+    else
+      nil
+    end
   end
 
   private
diff --git a/app/views/users/dossiers/show/_estimated_delay.html.haml b/app/views/users/dossiers/show/_estimated_delay.html.haml
index e33eab09c..93ddc0b36 100644
--- a/app/views/users/dossiers/show/_estimated_delay.html.haml
+++ b/app/views/users/dossiers/show/_estimated_delay.html.haml
@@ -1,10 +1,5 @@
-/ FIXME: remove the custom procedure switch at some point
-- procedure_id_for_which_we_hide_the_estimated_delay = 6547
-- procedure_path_for_which_we_hide_the_estimated_delay = 'deposer-une-offre-de-stage'
-- show_time_means = procedure.id != procedure_id_for_which_we_hide_the_estimated_delay && procedure.path != procedure_path_for_which_we_hide_the_estimated_delay
-
 - cache(procedure.id, expires_in: 1.day) do
-  - if procedure.usual_traitement_time_for_recent_dossiers(ProcedureStatsConcern::NB_DAYS_RECENT_DOSSIERS) && show_time_means
+  - if procedure.usual_traitement_time_for_recent_dossiers(ProcedureStatsConcern::NB_DAYS_RECENT_DOSSIERS)
     %p
       Habituellement, les dossiers de cette démarche sont traités dans un délai de #{distance_of_time_in_words(procedure.usual_traitement_time_for_recent_dossiers(ProcedureStatsConcern::NB_DAYS_RECENT_DOSSIERS))}.
     %p
diff --git a/spec/fixtures/files/data/treatment-expected-3months.csv b/spec/fixtures/files/data/treatment-expected-3months.csv
new file mode 100644
index 000000000..5107d80c1
--- /dev/null
+++ b/spec/fixtures/files/data/treatment-expected-3months.csv
@@ -0,0 +1,166 @@
+treatment_time
+1203843.06283
+673451.312319
+1552383.903455
+1558932.226583
+78953.851181
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+12436442.520349
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+12887043.034098
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+33533741.312976
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+20581103.945882
diff --git a/spec/models/concern/procedure_stats_concern_spec.rb b/spec/models/concern/procedure_stats_concern_spec.rb
index 9ab68e1e8..676085e21 100644
--- a/spec/models/concern/procedure_stats_concern_spec.rb
+++ b/spec/models/concern/procedure_stats_concern_spec.rb
@@ -30,7 +30,7 @@ describe ProcedureStatsConcern do
       Timecop.freeze(Time.utc(2019, 6, 1, 12, 0))
 
       delays.each do |delay|
-        create_dossier(construction_date: 1.week.ago - delay, instruction_date: 1.week.ago - delay + 12.hours, processed_date: 1.week.ago)
+        create_dossier(depose_at: 1.week.ago - delay, en_instruction_at: 1.week.ago - delay + 12.hours, processed_at: 1.week.ago)
       end
     end
 
@@ -40,37 +40,59 @@ describe ProcedureStatsConcern do
       let(:delays) { [1.day, 2.days, 2.days, 2.days, 2.days, 3.days, 3.days, 3.days, 3.days, 12.days] }
 
       it 'returns a time representative of the dossier instruction delay' do
-        expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to be_between(3.days, 4.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[0]).to be_between(1.days, 2.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[1]).to be_between(2.days, 3.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[2]).to be_between(11.days, 12.days)
       end
     end
 
     context 'when there are very old dossiers' do
-      let(:delays) { [2.days, 2.days] }
-      let!(:old_dossier) { create_dossier(construction_date: 3.months.ago, instruction_date: 2.months.ago, processed_date: 2.months.ago) }
+      let(:delays) { [1.days, 2.days, 3.days, 3.days, 4.days] }
+      let!(:old_dossier) { create_dossier(depose_at: 3.months.ago, en_instruction_at: 2.months.ago, processed_at: 2.months.ago) }
 
       it 'ignores dossiers older than 1 month' do
-        expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to be_within(1.hour).of(2.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[0]).to be_between(1.day, 2.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[1]).to be_between(2.days, 3.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[2]).to be_between(3.days, 4.days)
       end
     end
 
     context 'when there is a dossier with bad data' do
-      let(:delays) { [2.days, 2.days] }
-      let!(:bad_dossier) { create_dossier(construction_date: nil, instruction_date: nil, processed_date: 10.days.ago) }
+      let(:delays) { [1.days, 2.days, 3.days, 3.days, 4.days] }
+      let!(:bad_dossier) { create_dossier(depose_at: nil, en_instruction_at: nil, processed_at: 10.days.ago) }
 
       it 'ignores bad dossiers' do
-        expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to be_within(1.hour).of(2.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[0]).to be_between(21.hours, 36.hours.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[1]).to be_between(2.days, 3.days)
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30)[2]).to be_between(3.days, 4.days)
       end
     end
 
     context 'when there is only one processed dossier' do
       let(:delays) { [1.day] }
-      it { expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to be_within(1.hour).of(1.day) }
+      it { expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to be_nil }
     end
 
     context 'where there is no processed dossier' do
       let(:delays) { [] }
       it { expect(procedure.usual_traitement_time_for_recent_dossiers(30)).to eq nil }
     end
+
+    context 'with real data' do
+      include ActionView::Helpers::DateHelper
+      let(:delays) { [] }
+      before do
+        csv = CSV.read(Rails.root.join('spec/fixtures/files/data/treatment-expected-3months.csv'))
+        traitement_times = csv[1..] #strip header
+          .flatten
+          .map{ { processed_at: _1.to_f, depose_at: 0 } }
+        allow(procedure).to receive(:traitement_times).and_return(traitement_times)
+      end
+
+      it 'works' do
+        expect(procedure.usual_traitement_time_for_recent_dossiers(30).map {distance_of_time_in_words(_1)}).to eq(["3 mois", "6 mois", "environ un an"])
+      end
+    end
   end
 
   describe '.usual_traitement_time_by_month_in_days' do
@@ -79,8 +101,8 @@ describe ProcedureStatsConcern do
     def create_dossiers(delays_by_month)
       delays_by_month.each_with_index do |delays, index|
         delays.each do |delay|
-          processed_date = (index.months + 1.week).ago
-          create_dossier(construction_date: processed_date - delay, instruction_date: processed_date - delay + 12.hours, processed_date: processed_date)
+          processed_at = (index.months + 1.week).ago
+          create_dossier(depose_at: processed_at - delay, en_instruction_at: processed_at - delay + 12.hours, processed_at: processed_at)
         end
       end
     end
@@ -112,7 +134,7 @@ describe ProcedureStatsConcern do
 
   private
 
-  def create_dossier(construction_date:, instruction_date:, processed_date:)
-    dossier = create(:dossier, :accepte, procedure: procedure, depose_at: construction_date, en_instruction_at: instruction_date, processed_at: processed_date)
+  def create_dossier(depose_at:, en_instruction_at:, processed_at:)
+    dossier = create(:dossier, :accepte, procedure: procedure, depose_at:, en_instruction_at:, processed_at:)
   end
 end