Inventory googlesheet Formula Optimization and Format -- 2

My current Google Sheet tracks inventory levels across several locations, yet many of the calculations are either missing, throwing errors, or running slowly as the row count grows. What I need now is a clean, reliable set of formulas that can keep pace with our day-to-day updates without lag or manual intervention.

Here’s the core of the work:
• Create new, well-structured formulas where key metrics are still being calculated by hand.
• Fix every existing formula that returns an error or an inaccurate result.
• Optimise the overall sheet so large data ranges update quickly and do not slow other collaborators.

The data set includes SKU, stock-on-hand, minimum reorder point, location, and incoming purchase orders. Array formulas, QUERY, INDEX-MATCH, and maybe a touch of Apps Script for performance tweaks are all fair game—as long as the final file remains fully functional inside native Google Sheets.

Deliverables:
1. A working inventory spreadsheet with error-free, efficient formulas.
2. Brief in-sheet comments or a one-page doc explaining the logic, so anyone on my team can maintain it.
3. Confirmation that recalculation time stays snappy even after we add a few thousand more rows.

I’ll share view-only access first, then editing rights once you confirm the approach, and I’m available to answer any data-specific questions as we go.