<prompt> Human: There is no pre-payment penalty. I have the cash to pay 90 of the mortgage, but want to get the lowest rate possible. So thinking of doing a 5 year ARM, paying down 90 immediately then pay off the remaining 10 at the lower rate.1. Am I wrong to assume that a larger loan results in a lower interest rate?2. Would I have to pay a full month of interest on 100 of the mortgage, or just 1-2 days pro-rated?thanks!  <response>: First and foremost, when you pay it specify you want all of the extra funds to go to the principal. Some mortgage companies will consider them extra payments and just push your due date out like 25 years and rake in that sweet, sweet interest.As for the interest charges now, Im not sure - it could vary from company to company. 