Normal
The new open seating "anytime dining" option offered by Celebity which allows you to dine early if you wish does (for some reason) require prepaid gratuities at time of final payment and as I understand it cannot be removed for any reason from your bill. It is not a fee - just prepayment for what you would be charged anyway by Celebrity for the daily gratuities. Perhaps that is the "fee" your TA was referring to - if that is the case - get a new TA since they obviously don't research in order to explain to you what your paying for.