I wouldn't move it. I would chalk it up to TOM and wait til it's over to get your true wait. I weigh everyday, but my "official" weigh in day is friday. Whatever I weigh then I will change it to. However, if I know it's up from something like TOM I tend to be more generous with moving my ticker, and instead just wait til it's over.
For the most part, if I see a low number on the scale, I wait three days or so of consecutive low weigh-ins before I believe that I've gone down that much permanently.
When I jump back up by a pound or so, I tend to refuse to move my ticker back up, instead just redoubling my efforts to get myself back to where my ticker says.
I have an official ticker weighin (Sunday mornings). If it goes down I post it immediately, but for a gain I wait for the next week. If it stays up for two weeks, I'd adjust my ticker, but I haven't had that happen yet.
I move mine every thursday because that is my group's weigh in day, but before I had an official weigh in day I would not move my ticker until I seen that number on the scale 3 days in a row.
I move mine on Mondays too. If it's a new weight on Monday - like 189 when I've been 190 all week - I'll keep it at 190 until the next week to make sure it isn't a fluke.
I used to only move it on Mondays. Up or down, it reflected myMonday weight.
Now I move it every time I lose. I never move it back up. I've been weighing daily for over 6 months now, and I know every uptick is just water weight. Lately, I lose slow, which really just means I hit a new low, then spend 1-2 weeks (or more ) fluctuating a pound or two above that weight. But I leave my ticker at that low weight. I figure I got there, I earned it, and while I may be losing slowly, I know I am not actually gaining any fat. It's just water. It just feels good to lower my ticker every time I reach a new low. I guess that wasn't as true when I was hitting new lows all the time, but now they are much fewer and farther between.
If for some reason I thought I had truly gained, I would change the ticker. Honesty is what will get me where I want to be.
I generally just move it when I weigh once a week but I finally got my own scale so I've become slightly more obsessive compulsive about weighing myself. I moved my twice last week, once on Wed (I think) and again on Saturday I doubt it will be moving at all this week TOM is next week :S