You can just reach out to them and determine which one fits your needs the best.

@Eric Berkner  Depending on the other rents in your market and whether other owners in the area are billing for gas, will determine how much you can charge for it. 

I looked at enough properties though to determine my money would be better spent on other amenities. 

Lastly, if by "calculating", you mean performing a financial analysis to determine projected income, the answer is no it is not more difficult to calculate.

Trying to determine future appreciation, inflation, rent increase, tax depreciation, etc. becomes a bit nonsensical and is well outside of my wheelhouse. 

Some of the credit cards they get you do not report on your credit profile unless you don’t, But you would be the personal guarantor  and they would look at your personal credit As a determining factor. 

The amount of things that can go wrong are too many to count, especially when you have unknown unknownsI think whether you are doing it yourself or not should be determined by the size of the project.

I know the lender will have their own appraiser do an analysis to determine market rental prices, but the PnLs we've been getting from the current owners show only losses on what would be a new loan, so my lender has been pretty weary.

So, the calculator doesn't help determine condition of property.  

Eviction matters with a related pending ERAP application continue to be stayed until a final determination of eligibility for the rental assistance is issued by the Office of Temporary and Disability Assistance (OTDA).