A purchase order should start with records you can inspect. Past sales, stock that can actually ship, supplier commitments and product expiry all answer different questions. Combining them into a worksheet makes the decision easier to explain; it does not make future demand certain.
Collect the inputs separately
- Export sales for a consistent marketplace and reporting period. Note promotions, unavailable listings and unusual bulk orders beside the sales record.
- Record the supplier's stated production and transit commitments, the date they were confirmed and any minimum order or case-pack requirement.
- Separate fulfillable units from inbound, reserved and unfulfillable quantities. Amazon's inventory definitions explain why those states should not be treated as interchangeable.
- Keep expiry lots and storage constraints alongside each product. A large total can hide a shortage of usable stock.
Make the purchase decision traceable
Record the quantity a person proposes, the inputs they used and the uncertainty they still need to resolve. Ask the supplier to confirm changed commitments before treating them as settled. Preserve the worksheet with the purchase order so the next review can compare what was ordered with what actually arrived and sold.
The useful output is a documented purchasing decision, with clear responsibility for follow-up.