Dynamic Expense Allocation Template

I need an Excel-based template that lets me allocate expenses across multiple cost centres while easily changing the underlying rates or allocation methodology. The idea is simple: I enter the raw expenses and, through clean formulas and perhaps a driver table or drop-down, the sheet instantly redistributes the totals according to whatever percentages or rules I set for that period.

The workbook must be structured, locked against accidental formula edits, and fast—no lag when recalculating even if I drop in a few thousand rows of data. Because the allocation logic will evolve over time, please build it so I can adjust the driver table, add new cost centres or allocation keys, and have all results flow through automatically to the summary. Visual touches such as conditional formatting that flags outliers or missing inputs are welcome but not essential.

Deliverables
• A single Excel file with clearly labelled input, driver and output tabs
• Brief inline notes or a separate “Read Me” sheet explaining how to modify rates, add new cost centres, and expand the dataset

If you finish quickly and the sheet proves stable, I’m open to a short hand-over call or chat for any final tweaks.