What number is taxed on a financial statement?

[Marc Izquierdo]

I was starting to build, edit, and run a few deals through a spreadsheet I developed. Below is an example of the financial statement portion of the spreadsheet. I was wondering which number the IRS uses to determine your taxes at the end of the year. As you can see, at the bottom I just estimated 30% for taxes on my cash flow. However, is what I'm calling "pre-tax cash flow" (NOI - Debt Service + Cap Ex) the amount that I am taxed on? Or is it the GPI or EGI?

I was thinking about this while trying to analyze an owner-occupied triplex deal.  With three tenants, it produces positive cash flow (as shown below).  When there are two tenants (myself occupying one unit), it produces negative cash flow (about $300 a month - which I would pay).  In that case, my "pre-tax cash flow" is negative. 

This got me thinking about where the IRS takes their share.  If it is my "pre-tax cash flow" and if I live in a unit, then I show a loss for tax purposes, which would benefit me (doesn't seem right though).  Or does the IRS view me as a tenant and therefore my own money is "income" and I'm taxed on that?

Any input would be great.  Also, please feel free to critique my spreadsheet!

Thanks in advance!

FYI: This spreadsheet is based on annual income and expenses