or will they not go down until 24 hours have passed.
A 1 day trial means 1 day (24 hours) after the user started the trial, it will expire.
Everything I've read seems to state that you never write to the file.
You shouldn't modify the TurboActivate.dat file. However you can rename it whatever you want. You can also put it wherever you want (if you use PDetsFromPath() to load the file).