Cost semantics

Understand the date range, segments, four costs, and missing values.

Date range

month_from and month_to are inclusive ISO dates. month_to must not be earlier than month_from.

Value	Meaning
`normal`	Normal products only. This is the default.
`sample`	Sample products only.
`all`	Normal and sample products combined.

Field	Product-profit meaning
`purchase_cost_usd`	Purchase cost from the page’s available Landing split.
`inbound_freight_usd`	Inbound freight from the same available Landing split.
`shipping_to_customer_usd`	Shipping-to-customer total where costed rows exist.
`warehouse_fees_usd`	Warehouse-fee total where costed rows exist.

All four amounts are totals in USD for the requested range.

null means Mellow could not calculate that cost with the page’s current coverage rules.
0 means the value was calculated and the result is a real zero.

Do not convert null to zero. They represent different business states.

Unmapped source rows remain in the response. Their product ID and SKU may be null; clients should not silently discard them.