If the valuation method is one that causes that, such as FIFO, yes. Also I think it needs to be matched or told not to. Process Receipt of Invoice will print a register indicating a cost tier adjustment batch was created - you have to post it.

Thanks for your help.  The cost tier was created when AP posted paid the invoice.  Our problem was when the inventory was consumed prior to the AP invoice arriving. 

Yeah, unfortunately that's not an easy problem to resolve. We thought about this problem years ago and did some improvements to enable the adjustment when there was some inventory around - focusing first on the cost tier of that receipt. But, once the inventory is gone, the COGS took the amounts, so there's nothing to take the dollars from, except to do a GL entry to deal with it. At least that's all I can think of.