Catering mass on multiple legs
Let's say a European 737 is scheduled for -four- sectors with catering uplift only on the first leg. A gradual reduction of the catering mass, and corresponding CG movement, will occur as the day progresses.
Is there a legal requirement to update the Dry Operating Mass with actual catering on every sector, or can standard (catering) configurations be used; even on multiple sectors?
I've looked through CAT.POL.MBA, but none the wiser.