Agreed. I thought it was a generally accepted rule that votes counted until Thread Lock.
Before your time but early on when games were first played in the funhouse, hosts didn't have mod abilities to lock threads. Because of this, if the host gave a deadline of Midnight EST and your vote was 00:00:01 over that deadline time, the vote change didn't count and your previous vote stood. After all and having mods like Pale, S-U-P-E-R and Ty playing, someone asked or it occurred to the players that it might be useful to have them lock the thread at the day's deadline to prevent any over the deadline limit vote changes. Thus, even if there were cases where the thread was closed 2 minutes after deadline and someone changed their vote 00:00:01 seconds over the deadline, that vote wasn't counted even though the thread hadn't been locked.
However, later on, someone hosting just decided that the thread was open until locked and just tried to stick to locking the thread close to that deadline time. After awhile as other hosts sometimes logged on late to lock a thread, it just became the easier and defacto way to consider a thread and all vote changes made in it as valid until locked. That is the way it is mainly viewed unless someone isn't happy with the result and wants to argue it. Which is usually going to be Stevey blaming the back-stabbing, cheating, after-deadline-vote-changing mafia doctors and vote cancellers for breaking the rules and thus voiding their win. You might even get a vendetta thrown in for good measure if you are lucky. (I've been very lucky).
That is a little 101 Mafia History for you. All the details a host has to mention.