01
Build a simple crosswalk
Match each invoice line to a takeoff line using slate size, selection, thickness range, and quantity. Record whether the quantity is pieces, crates, or coverage. If coverage is quoted, include the assumed layout. Keep starter and special-detail material identifiable rather than merging everything under a single slate description.
02
Investigate differences before installation
A changed package count does not necessarily mean a changed piece count, but it needs explanation. Ask the supplier to reconcile any discrepancy with the delivery ticket and the installer to confirm the usable allocation. This process is most effective while packaging labels remain available. Save the reconciled schedule with the roof records for future matching and reordering.