Calculating private money into cost using brrrr

[Robert Stephan]

we recently watch the BP video concerning the brrr strategy and it looks great. However, when going through hownit work financially the private/hard money didn't seem to be calculated into the cost. Since the strategy relies on cash out refinance in most situations and you have to hold anywhere from 6mo-18mo before a bank would even consider a loan, how would this be a feesable strategey?