Inventory cost layer

A layer is more than “60 units at $12.” It is a controlled row for quantity and cost. The row also names the product or pool, date, source, unit of measure, location or status, and movement history. Those fields keep one product's cost out of another pool and make later depletion reviewable.

Start with supported opening layers. Add each purchase or completed-production layer on its event date. Apply each removal only to quantities available at that date when the records are perpetual. A negative layer means the schedule has a missing receipt, a date error, an inconsistent unit of measure, or an impossible removal. Stop and resolve the cause. Do not borrow units from a later purchase to hide it.

Two controls must hold. Ending units equal opening units plus additions less removals. Cost assigned to expense plus ending inventory equals goods available at cost. These controls prove that the supplied quantities and costs were assigned without a mathematical gap. They do not prove ownership, cutoff, qualifying cost, method selection, or the physical count.

ASC 330-10-30-8 makes the adequacy and consistent use of the cost accounting system part of the judgment. Paragraph 30-9 identifies FIFO, average, and LIFO as cost-flow assumptions. A layer supplies the controlled inputs for those methods; it does not select one.

Trace the controls in the Cedar example, then build the independent Northstar schedule.