@Angel5933 There's not a fee that's called the "hosting fee." Airbnb collects service fees for itself off of each booking, and hosts can choose whether those appear as inclusive ("host-only fee") or appear as added to the listed rate. But none of this is particularly relevant to a co-host, because your compensation is determined solely by the arrangement between you and your host. Airbnb has nothing to do with the amount that you get paid for your work, so what the new lady is doing is neither right nor wrong.
For co-hosting, I don't recommend having your wage pegged to the fees paid by guests. You don't want to take a pay cut every time the host offers a discount to fill a vacancy or loses a payout in an Extenuating Circumstances cancellation, and the work you have to do is basically the same regardless of what the guest is paying. But the best way to work out your billing plan really depends on how much autonomy you have in setting rates and selecting guests. I can only suggest that you set a firm contractual arrangement with the owner that clarifies what your responsibilities are and sets your terms of payment as an independent contractor.
