diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index 060370b57d4..df3ab9bb5bc 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -37,14 +37,18 @@ class table_compute(object):
         for p in products:
             x = min(max(p.website_size_x, 1), PPR)
             y = min(max(p.website_size_y, 1), PPR)
-            if index>PPG:
+            if index>=PPG:
                 x = y = 1
 
             pos = minpos
             while not self._check_place(pos%PPR, pos/PPR, x, y):
                 pos += 1
-
-            if index>PPG and (pos/PPR)>maxy:
+            # if 21st products (index 20) and the last line is full (PPR products in it), break
+            # (pos + 1.0) / PPR is the line where the product would be inserted
+            # maxy is the number of existing lines
+            # + 1.0 is because pos begins at 0, thus pos 20 is actually the 21st block
+            # and to force python to not round the division operation
+            if index >= PPG and ((pos + 1.0) / PPR) > maxy:
                 break
 
             if x==1 and y==1:   # simple heuristic for CPU optimization