The B1G1 40% off deal only works on games that aren't on sale already.
Actually, it's because the offer is for games $19.99 or less and they use normal pricing for exclusions
So because CE:A is in the system at $39.99 normally it doesn't qualify. But if the original price fit the criteria, it wouldn't matter if it was on sale or not.
At any rate, got mine this morning. Thanks to the OPs in both threads. And to the spaz flipping out over the duplicate threads: don't be such a spaz, guy, CAG isn't such serious business.