I don't work any radar unit up in that cold and windy place some call Scotland, but as long as you don't start flashing up the emergency squawks personally I don't really care how pilots change squawk. As long as the requested code appears within a reasonable amount of time that's good enough for me - I don't stare expectantly at a return to monitor what codes s/he cycles through to get to the one I want to see.
Of course, if I asked you to squawk 7742, for example, and you were already squawking 7000, I'd hope that you wouldn't cycle through 7500, 7600, 7700 on your way to getting 7742 on the box.
Probably not the answer from any books, but as a day-to-day radar bod that's my take.
