<prompt> Human: A friend of mine is buying a house, and the lender theyve been talking to seems to have this weird rule about monthly payments. The lender only allows payments each month to be a multiple of the regular monthly payment. For example, if the usual monthly payment is 1500, you can pay 1500, 3000, 4500 etc. This seemed sort of sleazy to me, like if can you afford 2000 monthly payments, the bank is getting quite a bit of interest while your money is sitting in your pocket until you have enough to make a 2x payment.Is this a common practice for mortgages? Is there something Im missingover reacting to?  <response>: If be willing to bet that theyre saying this because theyll just apply it to the following months payment and not applying it to principle. Its a red flag to me. 