There are just numerous variables and calculations you must analyze to check. 

I've been playing with amortization calculators and have seen you can pay off 1/3 of the mortgage and reduce 2/3 of the duration.

The BRRRR calculator may help you understand this better as the results are shown in three different phases - rehab, post rehab and then post refinance.

Look at the values of your 2 properties, consider any outstanding debt, calculate what your payment might look like on a cash out refi, compare that to current or potential rents.

@Marc Shin We're funding cash out refis for a lot of our most experience BRRRR clients right around day 91 (to pass 90 days of title seasoning) where we get the process started (appraisal, title, application, etc) around day 60  (plus or minus) when they have the place fully renovated and at least listed for rent (we'll use appraisers opinion of market rent to calculate DSCR). 

Sometimes they still have the garage door and drywalled the inside... meaning that they did not do a foundation on the garage door line : they did not use a deputy inspector, they did not use the appropriate hold downs (metals) for structural integrity, they did not use the right calculations for framing (ie rafters for ceilings ) that are often changed in a garage conversion... did not use proper headers for windows and doors... etc etc I have been faced with these a lot when representing the buyer and I would : 1.

Quote from @Sean O'Keefe:In your article you said, We had a recent court case which said in black and white: you cannot calculate an average if you do not have at least two numbers to average.Can you provide the court case reference? 

Helping Thomas calculate what he can close is the question.

I am assuming that these expenses should be factored into your budget prior to calculating your cash flow.

And I would argue purchasing is easier than managing.Luke 14:28-30 For which one of you, when he wants to build a tower, does not first sit down and calculate the cost to see if he has enough to complete it?