gozzbo:For example, a standard flop that works great on BP doesn't work worth crap on Oakmont...and so on and so forth.
The flop shot is just a wedge shot made with a much more open club face ( the reason it flies farther to your right) and trying to more or less "scoop" into the ball into the air by sliding the club under the ball.
That said, the simple explanation to your dilemma is that the bunkers around the greens at BP are normally 15-20% lies and around almost all of the other courses, they are 30-40% lies. The flop shot works so well on BP because of the tighter lie. The ball sits more on top of the sand and let's you "scoop" the ball out( almost like on the fairway).
I rarely attempt the flop from any of the "softer" bunkers just because the ball sits down in the sand more. You can't get that same kind of scooping action because you have dig thru more sand to get under the ball. Your best bet, IMO, is to hit a full shot or a punch, choking down no less than 50% on the meter.
I can't give you any more advice than that. You just have to get a feel ( or take notes) for each particular circumstance because there are a lot of variables.. elevation, green speeds, how much green you have to work with, wind speed/direction, how far from the lip of the bunker, etc.