Find all references to order number, subtract amount on current sheet from largest other

I have a sheet that I've been using to track both new and existing charges on a certain type of Work Order. In the attached workbook, I'm using a helper formula to determine weather an ORDER number on the current sheet was used on the prior sheet. Then another formula to calculate the difference in the amoujnt between the two. Do to a change in the reporting system the information is dumped from, I need to change the two formulas so that they look at all the other sheets in the workbook. If an ORDER number exists on one or more sheets the second formula nneds to calculate the current "Total actual costs" minus the largest other "Total actual costs" on any of the sheets. I've been trying some things with array formulas, but never really got the hang of them. Any help is appreciated.

I saved the file with the wrong sheet active. The sheet that shows what I'm tryiong to accomplish is titled "08-01 week 2". Thanks

Bumping, no replies

Bumping, no replies

I didn't imagine this one would be so difficult. No one has any ides?