I have adjusted data to pull older comps  and expanded the radius to include more data.  

Hi BP,I live in an 100 unit apartment complex in Westchester County, NY.

You probably want a few smaller units in one complex, or one larger unit or one that is differentaited in some way.  

Hi @Kyu Kim, I've done this before and the best part of it (in my view) is you can lock in low rate 30-year fixed residential financing on each of them separately while still having a larger complex. 

I also provide them with a folder with the agreement of sale (at least the page with the sales price) and copies of comparable sales with key data points highlighted such as price, date sold, sqft, etc.

The main problem is me inputting getting accurate Occ Rate and ADR numbers, but that's not a spreadsheet issue, that's a data problem.

If you’re still looking in the area I always love discussing investment strategies and market data.

While certainly as you mentioned there is room to improve it, I'd argue that the strength of the calculator is in the presentation the data is given to you in and the predictions they can provide. 

I'm buying a 16 unit apartment complex and looking to slowly renovate the flooring in each units.

Constructing a new property is a complex process but there are many instances where renovations can be more expensive.