Canadian Scanner Price Accuracy Code (Formerly known as SCOP). You need to mention SCOP and also the retailer must be participating in it to honour it, in your case Save-on-foods does.
When I went to Loblaws and bought two sticks of butter on sale, they rang up as full price and I showed her the sale sign and mentioned SCOP, so she gave me the first one free and I paid the sale price on the second stick of butter.