Brandon Turner million dollar article - numbers achievable?

[Charles Benkendorf]

Hi, I am just getting started with real estate investing. I read this article from Brandon Turner on how to make a million dollars in under 10 years: https://www.biggerpockets.com/renewsblog/2012/12/1....

It was a pretty interesting strategy, and I was following along but when I ran the numbers the criteria seem extreme. He did note that the criteria are high, but you can find these properties.  I want to lay out my numbers here and get a sense check! Am I wildly off in any of my assumptions / missing something? And secondly has anyone had deals in this ballpark before? 

Assumptions

• Goal is to cash flow $200 / month / unit
• Buy a property listed at 100k for 80k. Put 20% down, take out 30 yr mortgage @ 7% interest to pay for rest.
• Rent is $665 per month per unit, or 2660 for the building. This is the number I have to use for post tax cash flow to come out to 200 / unit / month.
• Using 50% rule, monthly NOI of $332.5 per unit, or 1330 for building. Cap rate is 20%! Seems very high but let's keep going to see where we end up.
• Mortgage payment of 426. Cash flow is 904 for building.
• Tax - monthly interest is 372 and monthly depreciation (27.5 yrs) is 242. Taxable income = NOI - interest and depreciation = 290 per month. Assume my tax rate is 35%, that's 102 monthly tax.
• -my post tax cash flow, what i can save for next building is 802 per month or ~200 per unit.

A cap rate of 20 seems high I usually see under 10%, maybe 11-13% for a lower income area. It's a 16% cap if you base on the listed price (100k) instead of purchase price (80k).

It also seems he excluded tax for his calculations but given the high cap rate, tax is not wiped out by depreciation and interest.