Ok to be clear:
Amex pulls EX 99% of the time. Sometimes they will double or triple pull as they deem fit. If they triple or double pull you, they will still provide you with only 1 score on the letter (from what I can tell from 2 examples...), unless you call and ask for your scores.
Discover is known to pull TU / EX predominanently, but they do pull EX in rare circumstances. Like every other lender, they might also double or triple pull as they deem fit.
Scorewatch provided by myFICO pulls EQUIFAX.
Not sure about what Discover monitoring service pulls.
AND on top of all that............there's all kinds of different versions for FICO calculations.
There's different versions of Beacon for instance.
There's also different formulas with emphasis on different areas, such as auto loan enhanced FICO, credit cards enhanced FICO, etc etc.
And of course, there's also a vantage scoring model that isn't FICO, that is sometimes utilized by certain lenders (i.e. Chase).
And there's also the internal scoring that each individual lender utilize.
Best way is for you to call whichever lender that provided you that score, and ask them what they used.
Yes, and I apologize as maybe Discover calls it Credit Score Tracker or something. I apologize if I confused anyone but I was going off of what it says when it's directly billed to my card. I guess I was ultimately confused because the difference in scores was upwards of 35 points....that's very significant. I hate that scoring Models could differ that much.