Repayment of the loan would be an automatic after-tax payroll deduction.

If you're looking to get into a more sophisticated job, dealing with commercial, development, ect, it will help and be required.Not sure where you were planning to go but there a a number of schools with real estate degree programs, some are masters.  

I have different PMs for the properties and I started my own spreadsheet for accounting gains and losses, but I was wondering if someone had a more sophisticated spreadsheet that I could use where I can aggregate all the data to know exactly how much I'm making on these properties. 

Most of them also have 10 or more on staff so they are running large businesses with the payroll and other costs to go along with it.  

You have to deal with real estate agents, hard money lenders or private money, project management, contractors, sub contractors, pay roll, insurance, timing the market, etc.  

I don’t think most people get this sophisticated in their deal analysis though.4. 

I must comply with all state and federal laws as an employer in the State of Nevada, including payroll deductions (FICA and Income Tax withholding), provide industrial insurance coverage and pay required unemployment compensation for that employee.If my project requires the repair, restoration, improvement or construction of a pool or spa, I acknowledge my obligation and duty to comply with the provisions of NRS 624.900 - NRS 624.930 (Inclusive).I acknowledge that I have received copies of NRS 624.900 - NRS 624.930 (Inclusive) and NRS 278.573 So going to court with a handful of paint material receipts and a the $500. spent on labor will cause the landlord to loose.

However, there are certain financial ratios that banks will want to see depending on how sophisticated you plan to get in order to show your a prudent steward of your own finances.

However, if you deal with sophisticated investors, to them owner-financing is a viable business plan !

There's one for sex offenders too.I also doubt that ex cons are so sophisticated that they're suing landlords for denying them based on their crimes.