Stock valuation
Remaining cost layers, oldest first — the order they will be consumed in. Valuation method: FIFO.
No cost layers yet.
Layers are created when a vendor bill is posted — that is where the real cost of stock is known. Until then, cost of sale falls back to each product's recorded unit cost, which still works and is still posted; it just isn't layer-based.
Historical stock received before this was switched on has no layers and will not gain them retroactively.