Monitor Credit & Identity
Get a Home Loan
Get a Credit Card
Get an Auto Loan
Credit Score Basics
Find Savings & Credit Cards
FICO® Ultimate 3B
3-Bureau FICO® Scores, Credit & Identity Monitoring
FICO® Essentials 1B
1-Bureau FICO® Scores & Credit Monitoring
FICO® Score 3B Report
3-Bureau Credit Report & FICO® Scores
FICO® Score 1B Report
1-Bureau Credit Report & FICO® Scores
Are you referring to the scores from here, ie the difference is in FICO version, TU98 vs EQ04 (or whatever the right values are)?
In general, the CRAs install (after paying of course) the FICO software on their systems, and run them on their data, using different algorithms as required by their clients.