Every time you refi, you hit the high interest first schedule to begin all over. Of course, if you are going to rock this mortgage by pre-paying enormously, that shouldn't make that big a difference to you. Nonetheless, I'd wait until Dec. 2016 and focus on pre-paying as much principal as possible in the meantime, rather than relying on some conservative appraiser's assessment of the value of your improvements. Use that ("shameful," as you described it) PMI payment to motivate you to pay ahead, pay ahead, pay ahead. Good luck.