The important feature is that the mortgage secures frequent and routine future advances to be added to the loan balance. A future advance is a clause in a mortgage that provides for additional availability of funds under the loan contract without requiring another loan.A primer on priority of interest in the face of commercial mortgage modifications and future advances in the State of Florida. Supreme Court, in distinguishing a mortgage for obligatory future advances from a trust deed in the nature of a mortgage, said:. For purposes of this section, the residuary clause is treated as creating a future interest under the terms of a trust. Each time a future advance is made, additional nonrecurring tax shall be paid on the amount of the advance. Addition of a future advance clause where none existed in the original mortgage, deed of trust, or deed to secure debt.