Rate display type "Secondary" should be participant enterable

Hi!

I have a primary rate standard that goes to an element with its respective input "Amount" with checked Participants enter value during registration, but I need to send another input "Total owed" of the same element with "checked Participants enter value during registration". I have created a Variable Rate Profiles assigning it to a "Secondary" Standard Rate with Calculation Method "No Standard value used" but when I put Assign on registration in Payroll Information, it sends me the error "There was a problem saving the elections because there is another registration in the same element that uses this registration (BEN-991105)" in addition to not letting me enter a value in my secondary rate and the default value is shown.