So in theory PPS should work quite much like M:AA and other F2P games.
Well, if the system worked fine for older games of this kind, it kinda makes sense that other games stick to it.

Guaranteed SR Gachas shouldn't have problems with this system, since the difference would be the maths that the program does to determine wheter you get a card or not.
Bad thing we can't put hands on the code to test it (without risking massive ban hammers LOL xD), but again, leaving the probabilities to the program avoids us the risk that our own biases represent.

Thanks Xanthius for the info.

Sorry for the topic detour!! xD ^.^U my fault