The LLC is claiming to have paid way more than the license fee. They paid $180,000 in fees plus $200,000 for insurance. So they claim to have paid far more than the $210,000 yearly fee.
Detroit says, the insurance money doesn't count toward the yearly fee. Hence the dispute over the amount to be paid.
It really appears that if someone wanted to work this out, they could have done so a long time ago. I think there is more to it that we will never know.