You have a credit card with an APR of $24\mathrm{.}99\%,$ monthly compounding, that has a balance of $$6,600.$ You want to transfer this balance to a different card with an APR of $8\mathrm{.}99\%,$ monthly compounding. Assuming that you will make minimum payments of $$160$ per month for either card, what transfer fee would make you ambivalent between transferring or not?