Without getting into a discussion that's only interesting to computer programmers, I would like to point out one of the functions of the boost control in the ecu.
Just before hitting the rev limit the ecu will lower the boost. This will help the 1st stage of the rev limiter (soft limit) to control the engine rpm's. With full boost still applied you would almost certainly hit the 2nd stage, which is the hard limit.
Now if that's not rpm dependent I don't know what is.