Need Feedback on subject to appraisal loan for Brrrr!

I found a lender that will loan 80% future ARV. I have to get list of repairs/upgrades, they appraise, them loan 80% of that. It is 12 months interest then converts to a 15-20 year amortization one time close loan. Can someone help me figure out if this would be a good Brrrr loan but just refinancing up front or what. Any Input would be great.