Hmm, you might have something there. I always manage to get either the 20 or 30% off and I don't go very often. But, if I get the 30, I'll do a big shop.
Before you buy, google the coupon code for free shipping. Used the PIES30 & the free shipping code (sorry, I forgot it already) about an hour ago to order a present for my nephew. Ended up being the same price as BF and since it was an online only item, I wouldn't have been able to get it in the store anyways.