Multi-Sheet Excel Formula Integration

I have a workbook with four to five related sheets and need a set of advanced formulas that will pull, process, and summarise data exactly where I need it. Some of these formulas must reach across the sheets—for instance, a lookup drawing values from a master sheet—while others can remain self-contained within their own tab.

You’ll start with the file as it stands today, review my current structure, then build or refine formulas so that:
• cross-references update instantly when source data changes,
• stand-alone calculations stay protected from accidental overwrites, and
• every function remains clear enough that I can maintain it later without hunting through nested syntax.

I expect the final deliverable to be the updated workbook plus a brief, in-sheet explanation (cell comments or a small “Read Me” tab) noting what each key formula does. Accuracy, speed of calculation, and tidy, readable logic are the success markers for this project.