If you're a practitioner, it also makes sense why it would be actual days rented vs days available to rent based on the mechanics of Sec 280A."

Like:  just cosmetic work, no mechanicals = $12 per sq ft. 

Nice to be mechanically-(ultra)inclined.

Its simply a mechanism for allocating property distributions and tax attributes in a manner other than a simple pro rata approach.

Mechanicals are great, it's just not super pretty.

The point being that during the inspection, make sure you review the condition and lifetime of all aspects of the property including; roof, mechanicals, windows, condition of units etc and have a plan.

That there are no unpaid or outstanding claims, bills or invoices for any labor performed upon or materials furnished to either the Tenant or Premises for which any lien or encumbrance including, without limitation, materialmen, suppliers and mechanic's liens, have been asserted or may be asserted against either the Tenant or Premises."

While some of what you said as it relates to the mechanics of the unit is a little over my head at the moment, that information was incredibly helpful and I will keep it in mind as I move forward! 

I am a Mechanical engineer by education but an investor/entrepreneur by choice.  

I am not sure where you are from, but there is a mechanism for this.