Last Purchase Price History

Dear All,

Is there any way we can have the Last Purchase Price History in SAP system?

Our customer has 2 stock transfer. In those 2 documents, she has 2 difference last purchase price on the document. But actually, she didn't issue any GRPO of that item during the period between the 2 stock transfer. So the last purchase price should be the same. How can I find out all the document during that period which may affect the last purchase price in the system? Thanks a lot.