Limp Mode? Or Computer?

My BMW tranny started shifting into limp mode frequently about 6 months ago. Took it to 3 different tranny shops (including the dealer) and all said it need to be rebuilt/replaced. The car drove great but if I rev'ed high during acceleration, the limp mode would engage. Made for fun trying to get on the interstate. I ended up replacing the tranny with a rebuilt unit and from day one, the problem was better but I am now again getting the same issue when accelerating resulting in limp home. Would it make more sense that the tranny was not the problem but the computer telling it how/when to shift was more the culprit? Limp mode? Thanks!