PAC Italy - FIFO cost if acquisition quantity is zero

Hello,

could you please explain the FIFO cost values for Periodic Average Costing?

I have CLE: Incremental FIFO Inventory Valuation Report output and for some items FIFO Cost for previous PAC period and current is the same, but for some items not.

How it should be? If acquisition quantity (buy, make qty) is zero logically FIFO cost should be left as in previous period.

Best regards,

Jelena