I would be careful with that. I haven't tried it with the demotion/promotion from MLB to AAA, but I tried it once with AAA to AA. I had a season where my AA was going to make the playoffs, but AAA was not going to be in the playoffs. The thought process was that my prospect (that was currently in AAA) had a high patience rating and if i demoted him to AA, he would not take a demotion hit, but the extra games he would play in AA would give him a decent year end promotion bump. Boy was I wrong, the demotion hit was huge. Not sure if it would be the same as a MLB to AAA demotion.
I have noticed that if you demote and promote right after a development cycle, it is usually fine. However, if you demote right in the middle of of a cycle (i.e 15-30 days after the players most recent development cycle, he takes a demotion hit.
If strikeout is correct above though, I think you should be fine. If you find out otherwise, please let us know.