If you think about it, its probably getting more air from your t3/t4 than it expects, therefore dumping more fuel it to keep it all nice and safe. And I've heard the PFC goes for "safety first" with its default map, so that it runs richer than necessary to protect your engine. After all, Apexi would figure the stock map needs to cope with big turbos, etc at least to get you to the tuning shop.
Really depends how much power you're actually putting out atm, but my guess is it just needs tuning before you're really going to know the exact point your AFM and/or injectors max out. But you're definitely right, if you're going for the big power you're gonna need all the mojo very soon