A relatively simple matter to adjust the calcs to suit, if one is willing and wanting to do so.
However, a greater problem is health and safety .. I recall, with some relief shaking of the head, a 727 multi sector duty starting off with meals for the later sectors.
Most fortunately, and a tad unusually, the girls brought up the first of the crew meals prior to feeding the folks down back. The F/E was first cab off the rank and went uncharacteristically quiet for a bit when he opened his meal pack. It was only a few seconds before both of us in the front caught a subtle whiff of what caused the F/E's reflection.
A near panic call to the cabin prevented any meals being distributed to the paying folks. An interesting discussion ensued with the base catering manager when we got back to the originating port .. by which stage the whole lot was a fetid, bubbling mess.