I don't know if this is going to help, but there are two annual credit report sites (at least!) One is freeannualcreditreport.com and the other is annualcreditreport.com. I didn't know the difference between the two until my daughter-in-law pulled her free reports from freeannualcreditreport.com, which is run by Experian. She was able to get all three scores which were based upon Experian's formulations, and were different than the scores pulled at the actual sites. This could be why your TC/TU scores don't match. One could have utilized the Experian formula and the other TransUnion's. If, when you logged onto the site (annualcreditreport/freeannualcreditreport), you weren't taken to the three individual sites, and had to create a profile for each, you may have been on freeannualcreditreport.com. This was our experience, anyway, when we went to pull her free reports.
I hope this helps.