Quantity application

Hello,

We have a customer that makes production in catering sector. Their cost application method is FIFO. Making credit memos and undoing sales lines are commonplace practices, because of human error and of the nature of the job done. But making item correction entries generally produces problems. For instance, there is a correction Item Ledger Entry record that corresponds to a sale. The posting dates, locations and item numbers (naturally) are exactly the same (variants are not used). But these two records have the same remaining quantities (with opposite signs of course), that is to say both of them are open entries. Item Application Entry table has an entry whose Inbound Item Entry No is the correction record and whose Outbound Item Entry No is the corresponding sale record. And that Item Application Entry also indicates that cost is applied.

Correction cost is seemed to be applied to the right sale record. But as respects quantity, the entries are open. What can be the reason for that type of working?