if i hold 12500 fun token, after 30 days if i hold bitcoin i get 2,5+4,08% - total 6,58% profit and after 90 days 9% interest on bitcoin or no?
No. You won't get an additional annual interest of 2.5%.
Your interest you get now will increase by 2.5%. This means that your interest rate will be multiplied by 1.025.
In the case you hold 12,500 FUN tokens, after 30 days, your annual interest rate will increase to 4.182.