I understand what you're saying, but as I earlier mentioned, when you flatten your fingers and play, how do you prevent the top joint of the finger from bending the wrong way? When that happens you loose alot of mobility and strength, and when I try to flatten my fingers, that always happens.
I'm still iffy about this whole flat finger thing, I mean, I have large hands and can play octaves and major tenths still keeping my fingers curved, so I guess my real question as well is what exactly does playing with flat fingers do to the sound that can't be done with a curve? I'm just confused.
try this:play with your wrist dropped DOWN (towards the floor) about an inch or 1 1/2 inches or so. At the same time, bring your elbows straight BACK.
All this boils down to obtaining the right "sound" and smoothness when you play. You will have to be the judge of when to play flat and when to curve, just remember, if it feels comfortable and sounds good its probably right. Now, if your teacher said you should flatten your fingers it may be because the transactions between black and white keys may be a bit forced and not have that "smooth" sound.
Anyone ever heard Marc-Andre Hamelin play? He has a credible technique, but in my opinion his playing style is very harsh and posessing little emotion....
Now my old teacher critcized one of my performances, saying that my fingers were TOO curved, and if I would loosen up and flatten my fingers I would be a more expressive player.