Find item offsets based on dollar amount

I have a spreadsheet I need help with. Hopefully I have explained it better, there is an explanation in the file I uploaded.

But basically, I am trying to look for offsets/cancellations for a certain item based on item ID and amount. But my results are getting flawed due to my many different formula columns.

I am sure I have complicated things more than they needed to be with my formulas.

Can you help? Thanks!

That worked awesome! Thanks!