Fees on the plan have been cut to £155 from £300 for customers with homes valued between £100,000 and £150,000.
Jon King, managing director of More 2 Life, said: “The cuts in application fees are in direct response to the strong early demand.”
More 2 Life’s research showed up to 103,000 over-65s are still paying mortgages, spending around £1.36bn a year. That breaks down to around 81,000 households in the 65-74 age group and 22,000 in over-75 age groups.
And it forecasts the issue is likely to become a bigger problem as more homeowners with interest only mortgages come to the end of their term.
Application fees now range from £120 on homes worth less than £100,000 to £820 on homes worth between £800,000 and £900,00, compared with £200 and £900 previously.
King said: “The Interest Choice Plan is expanding the market by improving on previous plans which offered interest-paying options and offering increased flexibility on access to further funds.”