So, here are the numbers for the mortgages:

1. Original. Total interest = 91657

2. Original w/ prepay 1/12 = 80064 (total monthly = $1439 + escrow)

3. New %3.375 w/ 189 prepay (to match 1439) + what was paid already = 72508

4. New %3.125 + 1700 add to loan w/ 207 prepay (to match 1439) + what was paid already = 66743

5. New %3.125 + 1700 upfront w/ 217 prepay (to match 1439) + what was paid already = 67298

you're doing this math all wrong. you shouldnt be comparing total interest. and you really shouldnt be prepaying at any of these rates.

its a simple math equation to figure out how to REFI.

take your current loan balance at your current rate and put it in the google mortgage calculator then take your new rate and current balance and put it in that calc. take the difference in the 2 multiply it by 12 thats your annual savings at the new rate. now if you're doing a no cost obviously the REFI wins.

If you're doing a cost loan you take your cost to REFI divided by your annual savings and this gives you your payoff window.

at this point its a gamble you can only REFI every 6 months typically. so now you have to decide do i think rates continue down and just do the no cost and if they go down i'll REFI again in 6 months ... or do you think they will recover and you can not REFI in 6 months or anytime during your payback window.

thats where this choice lies ... i'd quit looking at total interest b/c its not relevant IMO.