Lesson Learned - Ralph's Coupon Policy

We stopped by Ralph's yesterday to take advantage of the Purex and Coke Deal. (We plan to return for the other groceries we need on Tuesday, but really wanted the diet coke!) I got three of the Natural Element Purex Detergent. They smell great! I got to the line and gave them my 3 Q's thinking all of them would double ($.35 to $.70), but only one did. I was bummed. Then I was checking out Hotcouponworld.com last night and came across Ralph's coupon policy. They only double one of like kinds. SIGH! I was under the impression they doubled everything as long as it was under a dollar. In conclusion, if you plan on stockpiling an item and want to take advantage of double coupons, you have to make separate transactions.