Recently I've incurred in a situation analogous to what explained here: Changing acceptance after a long time
For a question of mine, I had accepted an answer by JPi but then I accepted another by egreg.
Even if I prefer egreg's one, the two answers were similar and both good, so I was sorry to take away 15 points from JPi's reputation.
In these cases, is it too complicated to decrease JPi's reputation only by 5 points or to trasform the previous acceptance in a (second) upvote by me?
Obvioulsly only once per answer, otherwise I can switch between Jpi's and egreg's one again and again and make their reputation go to infinity.