diff --git a/kfet/templates/kfet/kpsul.html b/kfet/templates/kfet/kpsul.html
index 1a177dcd..a78028bf 100644
--- a/kfet/templates/kfet/kpsul.html
+++ b/kfet/templates/kfet/kpsul.html
@@ -774,16 +774,27 @@ $(document).ready(function() {
     }
 
     function addPurchase(id, nb) {
-        var amount_euro = amountEuroPurchase(id, nb).toFixed(2);
-        var index = addPurchaseToFormset(article_data[1], nb, amount_euro);
-        article_basket_html = $(item_basket_default_html);
-        article_basket_html
-            .attr('data-opeindex', index)
-            .find('.number').text(nb).end()
-            .find('.name').text(article_data[0]).end()
-            .find('.amount').text(amountToUKF(amount_euro, account_data['is_cof']));
-        basket_container.prepend(article_basket_html);
-        updateBasketRel();
+        var existing = false;
+        formset_container.find('[data-opeindex]').each(function () {
+            var opeindex = $(this).attr('data-opeindex');
+            var article_id = $(this).find('#id_form-'+opeindex+'-article').val();
+            if (article_id == id) {
+                existing = true ;
+                addExistingPurchase(opeindex, nb);
+            }
+        });
+        if (!existing) {
+            var amount_euro = amountEuroPurchase(id, nb).toFixed(2);
+            var index = addPurchaseToFormset(article_data[1], nb, amount_euro);
+            article_basket_html = $(item_basket_default_html);
+            article_basket_html
+                .attr('data-opeindex', index)
+                .find('.number').text(nb).end()
+                .find('.name').text(article_data[0]).end()
+                .find('.amount').text(amountToUKF(amount_euro, account_data['is_cof']));
+            basket_container.prepend(article_basket_html);
+            updateBasketRel();
+        }
     }
 
     function addDeposit(amount, is_checkout=1) {
@@ -903,8 +914,8 @@ $(document).ready(function() {
     function addExistingPurchase(opeindex, nb) {
         type = formset_container.find("#id_form-"+opeindex+"-type").val(); 
         id = formset_container.find("#id_form-"+opeindex+"-article").val(); 
-        nb_before = parseInt(formset_container.find("#id_form-"+opeindex+"-article_nb").val()); 
-        nb_after = nb_before + nb;
+        nb_before = formset_container.find("#id_form-"+opeindex+"-article_nb").val();
+        nb_after = parseInt(nb_before) + parseInt(nb);
         if (type == 'purchase') {
             if (nb_after == 0) {
                 deleteFromBasket(opeindex);