Hi Tzeching,
I believe I was in Jennie's class with you. I had the same thing happen when they first started the $4 off 4 and the cashier actually gave me cash back! I was in the self-checkout line but I was stunned when he handed me $2.15 in cash. I had split up my transactions because I was trying to make sure my coupons worked correctly.
Also, don't get discouraged if you get crabby people giving you a hard time about your coupons. I've had those but I've also had people ask me how I could possibly save that much. They do look at me sometimes like I must be doing something illegal to buy so much for so little money! 