How to clean up Service Desk manual entries after Desktop Central interface live?

I'm working on cleaning up our asset list in Service Desk. We had many manual entries, some with missing asset tags or manually entered computer names. We were also using the SD scan functionality.

Once we got Desktop Central working, we're finding we have multiple items that we need to clean up. I know the SD scan matched to entries by computer name, asset tag, and MAC address.

When Desktop Central pushes its scan information over to Service Desk, which field does it use first to find a 'match'? The Asset/Service Tag? Then the computer name?

We have relationships and some manual entries in SD that we need to keep, so we can't do a wholesale clear/repopulate from DC. If I knew the main field used in the actual match being done on the xml file I could make sure the proper fields are updated in SD.