@Account Closed,
Depending on how you finance the acquisition the benefits of BRRRR can vary.
Situation 1: Private Lender or Hard Money Lender agrees to fund 70% ARV which is $105k based on your hypothetical. They will withhold the $35k in repairs and release them to you in draws (so make sure you have a line of credit or cash to get work started). After the house is repaired you immediately file your refinance paperwork (I'd have it filed before hand, but the appraisal can't be ordered until the repairs are completed). There is no need to wait 6+ months to refinance. You can typically get up to 75% ARV on the refi. In this situation, other than closing costs, you have very little out of pocket expenses. Your ROI / CCR will be great and your cash flow will jump when you lock in the lower interest rate. I've used this strategy many times!
Situation 2: You do the same as the above except you use cash for the acquisition and repairs. I have not done this before. There may be some seasoning required (6-12mths) before you can do a cash out refinance. Once you refinance though, you will free up your cash to do other deals. This may "save" you on costs by not using an acquisitions lender, but you are tying up your cash that potentially could have gone towards other deals (opportunity cost).
Situation 3: Instead of using a PL or HML, find a local portfolio lender. Some will lend 60-70% ARV and hold repair reserves just like a HML. The difference is their rates are usually much better than HML. I did this recently and the loan was about 4% with 1pt. It was much better than 12% with 3pts. Plus, you don't have to pay for two closings. However, many portfolio lenders will want to see skin in the game so you may have to put some cash down regardless of how cheap you buy it. They will also want good credit and experience.