What do you mean Congress wasn't informed? The CRS report that is linked literally includes a link to the DoD IG report that was delivered to Congress.
Are you saying that this unclassified report (both the inital DoD IG report, and the later CRS report) are underreporting the actual losses?
BTW - the only thing that appears missing from the DoD report is a listing of the intentional destructionn of the 2 MC130s that were stuck in the sand during the CSAR OP. No idea why they aren't there (maybe they are included in a classified version), by the time the report was issued all the OPSEC reasons and optics reasons hide the info were long gone