Are different groups of rows (OnHand, ... , ProjOH) different projects?

You'd make your life much easier building your table(s) vertically! And then having a report sheet where user sets report conditions and gets result table.

E.g. sheet "Registry" with columns like Week, Project, OnHand, SupplyQty, DemandQty, ProjOverhead.

With such design, once you have all formulas in place, there is no need to edit them in future. You simply add new rows into table. And when the workbook slows down because of too many rows (think of tens or hundreds thousands rows - depends on amount and difficulty of formulas in report sheet(s)), you save a copy of old workbook as archived one, and then delete a bunch of older entries.