I think the only thing this calculator does not factor in is capital expenditures. 

I think the 2% you are talking about is to fix general wears and tears, not capital expenditures like roofs. 

You might be able to more deduct the expense in the same year as well under different code( sec 190) see below.Remember, expenditures unnecessary for compliance with the Americans With Disabilities Act of 1990 (ADA) are not eligible.If you spent more than 5k in both removing the barriers and making changes for the compliance,  you can deduct other expenses up to 15k rather than capitalizing and depreciating it. 

Don't forget to account for vacancy, repairs, capital expenditures, property management (even if you self-manage, there will likely come a time when you don't want to), and water/sewer (if you pay for them). 

Make sure to include monthly expenses for lawn care / snow removal, insurances, any utilities you'll pay, repairs/maintenance, capital expenditures, vacancies, taxes, etc.

I have been in the construction industry for a long time and I see many investors struggling with different aspects of investing when it comes to repairs and capital expenditures.

We do not anticipate any major capital expenditures for this property right off the bat. 

I have experienced the issues landlords go through like unforseen evictions and capital expenditures.

Capital expenditures hurt a lot more in lower priced houses.

No, those numbers do not account for vacancy, maintenance, capital expenditures etc.