Subtract the 5k in taxes and three years from now I’m sitting at roughly 20k earned by moving the funds from 401k to the property. 2) By moving the funds from my 401k, I lose on having to pay 5k in taxes, and the anticipated 6-9% return on the 401k as it sits in the fund.

Once you subtract any flat fee that you're paying and any marketing costs, and accounting for your time, it's often not very beneficial to try to do it yourself.I've been in this industry as an agent and investor for 15+ years.

But if we do it right we will subtract mortgage, tax, insurance, vacacny, and Cap Ex to get a difference of $425 which is $5,100 of annual Cash Flow.

I was subtracting the mortgage payment.  

Subtract the average annual inflation rate of 2.1% you don't have much left. 

Next subtract the optimism along with a few percent and decide if a heloc would make sense.

So at the end of each year we will subtract the management, accounting, and repair/maintenance cost from the 11,250 I owe him.

Subtract broker's commission and principal balance.

Without doing the math hard to know if you found deal or no deal...... some percentages like tax rates & realtor commissionsaddition & subtraction fractions 5 out of 12 months leftdivision mainly by 12. 

So.... 1/2 the expenses of the duplex are deductible... ( or you depreciate them depending on what they are...) and any expenses directly attributable to the rented side come off the income ... it doesn't depend on the amount of rent as much as the total after you subtract the expenses from the rent.