Although new translations start with 0% or 100% match in TMS if a translator applies a desktop TM or edits the segment the original TM % match is overwritten. We have no way of know what kind of TM leverage the original bilingual file got from TMS TMs. This information should be retained and be visible for each segment regardless of how it is edited during the translation/editing process.
This becomes a real issue if our editors are only asked to review items that are not 100% matches.