This also helps with tax planning so clients aren't blindsided.The tools/software that clients use is as varied as the clients themselves. 

If it is a contractor that is more organized they will likely do this already, if they are shooting from the hip "based on experience" they will likely just give you a total $ value. 

@Jason Brown - I'm a CT based investor, flipper, and property management company owner.  

Quote from @Christian Styles: Hey Sam, I've used both Propwire and Propstream, they seem quite similar but propwire has a free base version and propstream does not.

Pay the bill yourself, then reimburse yourself by charging the tenants based on a formula.

Materials will be about the same, but labor may vary greatly on location.

Yes, as S-Corp owners deferring salary into a Solo 401(k), you must still pay FICA taxes (Social Security & Medicare) on the deferred income since FICA is based on W-2 wages, not taxable income.

I've used Propstream, Red X and Real Estate skip trace with varying levels of information accuracy.

The guest house has STR rental history but the other two units would need to be based on projections. 

In the end, buyers would overpay for the actual property based on earnings.