First Apartment Complex. What did I miss?

[Kyle Johnson]

My Wife and I currently own 2 rental houses free and clear and a duplex.  We are now looking into buying our first apartment complex.  To do this I am going to need to sell one of our rental houses in order to have cash for down payment.  This apartment complex is a 26 unit.  I am in the beginning stages of research.  When I put my spread sheet together everything looks great.  But what worries me are if there are underlying issues that I am not seeing.  I do plan on self managing this property.

Any feedback is so appreciated.  

Apartment Excel Spreadsheet Breakdown