Do Shopify purchase orders update cost per item?

What Shopify says

Shopify’s guide for merchants moving off Stocky states that each variant has a single static cost per item and that this cost stays fixed when you receive a purchase order or transfer.

So a purchase order and a product’s cost are two separate records:

	Purchase order	Cost per item
Holds	What you agreed to pay on one order	One current cost for the variant
Changes when	You edit the order	Someone edits the field
Affected by receiving stock	Quantities received	Nothing
Used by profit reports	No	Yes

Where the gap bites

You order 300 throws at $21.40. The variant’s cost per item still says $19.80 from the last order. You receive the stock, sell it, and Shopify reports every sale at a cost of $19.80. The purchase order had the right figure all along.

Carrying a new price through

When a supplier’s price changes, treat updating the cost as a step of receiving:

1. Receive the purchase order.
2. Compare each line’s cost with the variant’s cost per item.
3. Decide what the new cost should be: the new price, or an average weighted by the stock still on hand at the old price. See weighted average cost.
4. Update cost per item, in bulk if there are many lines.

Extra costs on a shipment

Shopify lets you add cost adjustments, such as a shipping amount or customs duties, to the shipments of a transfer linked to a purchase order. They appear in the transfer’s cost summary so you can compare agreed and actual cost. They are not added to cost per item.

Options beyond the manual step

• Costing apps that work from receipts update cost per item when stock arrives, usually on a weighted average, and some spread freight and duty across the shipment.
• Cogsy does not read purchase orders. It keeps the dated cost for each variant: enter or import the new price with the date it applies from, keep each supplier’s price side by side, and write the figure you choose to Shopify.