The point about multiple accounts is an excellent one. But with multiple accounts you can't remove the first vote at all, only add to it or subtract from it with a downvote. Not exactly the same thing as changing.

Though if one can argue that the multiaccount solution is strictly better than changing, that is an argument for allowing changing, but not to the extent that it may convey further advantage or disadvantage others. Some aspects of this may be very difficult to realize in implementation.

But when it comes to the votes before such an adjustment, I don't see the conceptual difference between an event in which you change your vote significantly and an equivalent vote by another account

I believe you are talking about votes which are sequentially previous? In that case I agree, which is why I said that when your vote is last, changing it can be allowed without penalty.

But...on second thought even, that is not entirely true. Your vote might have discouraged others from following and then once you remove your vote the auction timer would be burned down. I believe the rule about allowing the last vote to change with no penalty can only strictly be applied after the penalty expires (so that mere passage of time does itself not change the state of voting).

especially in cases where one makes mistakes, which you mentioned

Another rule variant I've considered aside from being the last vote as I mentioned is to allow vote changes without penalty or with reduced penalty for some time period, say one minute, even if no longer last in the stack. Subsequent voters can consider that previous votes are not yet 'final' until the timer has expired.