I am sure there is an explanation for this but I have a calculation field set to add a numerical value if a date is entered into another field. A related table then uses the numerical value as part of a calculation in the related table. My original table then enters the related calculated value in a field. It only does this for the record I was working in. I then have to click in the field of each of the other related records for the value to change. Is there a way round this? I could write a loop script that starts at the first record and enters the field in question of every record in turn but can't help wondering why it doesn't do it automatically.

You could probably use a Refresh Window [ Flush cached join results ] step. I say "probably" because I don't follow the entire procedure. Perhaps if you explained the purpose behind this exercise, a simpler method could be found.

Sounds like you could write a script trigger, but I just do not have enough information to totally agree with that as a solution.