I don't believe that is correct. According to what I have read, the assistants receive a bonus for 7 wins, but Kirk needs to get to 8 wins to get the $500, 000 bonus.
True, but with 7 wins, KF's guaranteed salary for 2022 jumps from 50% to 100%. So, he essentially gets about a $2.5 million "bonus" for 7 wins this year. The extra $500K for winning an 8th game is chump change compared to that.
https://www.landof10.com/iowa/kirk-ferentzs-iowa-contract-includes-creative-buyout-language