I am in the process of building a spreadsheet that utilizes formulas, buttons, macros, and hidden sheets that contain my lease agreement, lease extension, work orders, all tenant letters, and more to simplify some of my important business processes. 

May be I over simplify things, but that is what I do.

, it would simplify my financing.Would it be advantageous to him to seller finance?

For An over simplified example Say your total gain on a property was 7% after you sell it and your tenant paid every bill from the day you purchased it.

It they are not on the lease, it can really simplify the job of the landlord.

That was very well explained and I really enjoy reading something when someone simplifies the explanation like you did using attention to detail.

If you decide that you may want to pursue this route, please note that I have simplified things and there are further complications and requirements. 

There is an option called a qualified contract (Q/C) where you can put the property up for sale (at 15 years) and if no one buys it (I'm way over-simplifying this) to operate it as LIH, you can get out of the LURA2) Year 30 - THe LURA burns off and once the leases in place expire, you can go market-rate.

Its supposed to simplify rent collections for landlords amongst some other things.

A consolidated, simplified portfolio.