Don't really like the sound of this one - in busy scenarios, you don't want delays in a/c executing instructions and the reconfirmation IS going to clog up the r/t.
By all means check if you're not sure about the instruction, but as the last post stated, an individual crew member should be trusted to carry out an executive instruction without screwing up!
MACC and LTCC both have Mode S, so incorrectly set levels on the flight deck of Mode S enabled a/c can be detected.