The 800,000 provident fund loan will be paid off in 25 years, and the principal and interest will be repaid in equal amount, so the total interest of each contribution is 369,558.94 yuan. If the principal is repaid in equal amount, the principal will be repaid by 2666.67 yuan per month, and the interest expense in the first month will be reduced by 7.23 yuan or 7.22 yuan compared with 1 month, and the last repayment will be 7.22 yuan, with a total interest of 326,083.33 yuan.