My item has only got 1 item receipt. However, the ‘Average Cost’ and ‘Last Purchase Price’ are different
Average cost is calculated as a weighted average for on hand inventory, where Last Purchase Price only reflects the last positive inventory posting transaction (Item Receipt, Inventory Adjustment/Transfers, etc.). For example….if you have 5 units on hand at an average cost of $1.00, and then you receive another 5 units at $2.00, your average cost will become $1.50 but Last Purchase Price will show as $2.00.
You will need to find and review the transactions affecting your average cost, more than likely there is one which does not match the LPP exactly. It is possible to update the cost on historical transactions as long as the accounting period is open so you could update that with the corrected value, otherwise an inventory adjustment worksheet can “reset” the inventory cost valuation as of a specified date.