Auto remove hours

Hi All,

I've been pulling my hair out to try and find a solution to my problem.
I am trying to automate my time sheet...

One column has the basic hours I am rostered to work in.
One column total hours worked in
one column has the additional overtime hours in

I work shifts, so each day has 3 sections to it:
07:00-14:00
14:00-22:00
22:00-07:00

Here is the problem:
If I am supposed to work 0700-1400 but they change my shift to say 1400-2200 I have to show what shift I was supposed to work but crossed out as well as the shift I actually worked.
So when I total up the hours worked in that column it would have an extra 8 hours in the total.
Is there a way to automatically lose the additional hours?
I have tried using the difference between the rostered + overtime and taking that from the total but keep getting a circular formula.


any help appreciated.