I'm running with timescale 3:1, and the rate of dehydration still seems appropriate.
Hmm.. perhaps it is only me, then. Some sort of bug. My dehydration and starvation is normal otherwise, I just seem to lose absurd amounts when I wait or sleep specifically. Would you mind saving, checking your level, and waiting 1 hour and let me know the difference? It would be greatly appreciated. I'm about to load up a new game here, set the time scale, and see what happens.
Thanks for your time.
Edit: I loaded up and had the same problem still, here are some numbers - timescale at 6, waiting 1 hour: gain 60 dehydration. timescale at 30, waiting 1 hour: gain 12 dehydration. the numbers seem to add up right at least. Still not sure why it would work like that though, shouldn't it go off of game time passed?
Edit 2: Ok, I figured this out. The dehydration rate is the same as far as I can tell unless the timescale is at 1 or 0. In real time this means the rate will seem the same as you go along no matter what. The problem is that when you sleep, wait, or fast travel as well I assume, that it calculates how many times your dehydration is hit by your time scale. It goes in increments of 6, so if your timescale is at 10, you would be hit 6 times in a hour for 6 each, or 36 dehydration. If your timescale is at default, you are only hit 2 times per hour for 12 dehydration.
I suppose a mod could be made to dynamically change your timescale when you try to sleep, wait, or travel and then change it back to your desired setting. Or you could just alter the "needs" rates in the GECK to match the new multiplier you chose in game. This would result in slower paced needs as a whole, but maybe thats not such a bad thing considering you would change the timescale just for that kind of slower paced game in general.
I would personally prefer to keep the difficulty intended intact and simply have days that aren't over in a blink, but I don't have the know how to fix this myself.