Changed item codes, but can't generate a report on these?

Due to some billing changes, we recently updated a whole group of item codes in Front desk to allow for more variations. I am now trying to run a report on one of those old items, but it seems to ignore anything before we changed the code... I also can't seem to generate a report using the old codes? Any help would be much appreciated! It is a product not a consult so I can't use appointment filters either :(