Do you know of any mortgage compaines using FICO 8 score for loans?
You won't find any.
The vast majority of mortgages are underwritten to the rules of one of the GSEs, and they require the use of three specific score models (EQ5/TU4/EX2).
Even in the cases where a bank intends to hold the loan, rather than selling it, they effectively always use those three scores (all their internal risk models are already setup for the Fannie/Freddie rules...)
Unless you're looking at a hard money loan or a really unusual credit union (that holds it's own loans), you just won't see anything else used today.
(And if a new scoring model is switched to at some point, it's possible/likely that the various score/rate breakpoints would be different.)
FWIW - Here is a comparison table on how VS4/VS3 and F9/F8 views some important scoring attributes
Below is a link to an article on Fico score distributions from TransUnion which compares Fico 04, Fico 08 and Fico 09.
Note the upward shift at the top end with the newer models.