People can make additions or subtractions with no permits.

I plugged all the numbers into the Rental Property analyzer calculator, as modest as possible trying to determine what my unit would cost me after subtracting all other expansive, for example, 5% on Maintenance, vacancy, capital ex, and 11% management fees. that number is roughly $900 a month or $10,800 yearly that I would be responsible for. both scenarios look like this  A) Primary Resident: 69k (10% down + closing) +10,800 = 80k the first year VsB) Investment Property: 159k (25% down +closing) - $4704 ( $392 monthly cash flow) = $154,296 first year I feel that option A is the better option in year 1, but I can not figure out a true representation moving forward after the house hack is done and I replace myself with a tenet?

Calculate how much you could collect from rent and subtract that from the monthly mortgage.

, then subtract a reasonable utilities cost from the gross amount, ie. $200-400/month depending on the size of the property.

What we don't have is some type of spreadsheet/tool that helps us forecast the revenue from our portfolio out multiple years and what impact adding/subtracting to the portfolio will have? 

When you sell, you subtract your basis in the property (the original cost and any improvements), and the remaining amount is a capital gain.

@Fox Barolo first thing that jumps out is in your photo/analysis it looks like you forgot to subtract the monthly expenses noted, so your monthly net is actually going to be $700. 

In Illinois, where I live, there are lots of covenants about adding or subtracting units, and I would guess NJ is similar.Structurally, you'll need an architect and a contractor to pull it off.

I would subtract escrow from the $7000 and figure out what accounts for the difference.

So they are already deducting the expenses like taxes, insurance, utilities, etc; and want to cover vacancy etc, above that.eg ...if gross rental income is $1000 per month and  the  25% vacancy  factor  is being used  ..the  adjusted  rental income would  be  $750 .....you  would then  subtract the PITI for the rental  to come up with the monthly positive  or negative monthly rent  figure that is used