You will never owe more that your house is worth. In most cases, homeowners have money left over when the loan is repaid. The amount you owe on the due date will not be more than the fair market value, as long as you have met your mortgage obligations (remained living in your home, paid your property taxes and insurance, and kept your home in good condition).
Your home should continue to appreciate in value and offset interest costs and loss of equity. The amount of equity remaining in your home will depend on the current value of your home and the amount owing on your Benson Reverse Mortgage.