<prompt> Human: EDIT - thanks for the help everyone. I called my lender and asked that the extra payments be transferred towards the principle of the loan. Consequently the loan balance dropped quite a bit and loan balance TBD the next payment is due next month. Ive been getting my finances in order over the past month and finding so many errors that are a result not monitoring my accounts. The most embarrassing is that due to a bank error I was making 2 full payments on my mortgage each month for the past 12 months. Now that Im ahead I want to figure out how to make the most of this. 30 year fixed loan circa 2005, 6.5, monthly payment 820 PITI, house is a rental unit generating 9XXmonth. --- EDIT ---I just pulled a loan payoff quote. The Principle balance is 55,XXX but the payoff amount is 50,XXX and under the line item for interest it shows -5,XXX. ---EDIT ---Our financial situation is deleted for brevitySo back to the loan payments - my payment history shows that despite making 2x payments I havent paid on interest since May of last year. Why not? The lender is still holding the debt and has costs. Is there any way possible this is going to continue forever making principle-only payments? Is my optimal monthly payment 1X PITI, 2X PITI, or just PTI? Or maybe dont pay anything until my next payment is due in December 2017?And finally, is this going to backfire on me somehow? TIA  <response>: sounds like the bank has been just paying your loan up in advance. Back in the day when i worked at the bank, we would have to specify in our system if any additional overage from the original payment was to be applied to principal. If nothing was stated, then it was just applied as prepaying your loan which only benefits the bank. Always be sure to specify that additional funds over the normal payment are applied to principal. 