The theme in your responses seems to show that is more important to you than your selling price/interest rate.Based on solving for the new buyer:Purchase Price: $200kDown Payment: $10kLoan Term: 30 yearsInterest Rate: 6.5% (fully amortized)5-year Balloon: ~$181k (this isn't exact but is in the ballpark)Again, you can't mathematically have *all* of the parameters that you desire so you need to decide which ones to tweak to make you and the potential buyer happy.

IRR is just a mathematical solution and can get nonsensical when there are lots of ins and outs (you can have cf's that do not have an IRR or have multiple solutions...multiple IRR's). 

You can disagree all you want about my opinions but that's plain mathematics and mathematics ultimately tell the truth.

One more thing...I really enjoyed the fact that you guys took the time to mathematically equate my expenditures, gains (ROI).

I should definitely start doing this to get some first-hand experience with the area.I have a degree in Mathematics and work with numbers daily so I definitely understand the importance of being comfortable with the quantitative side of things.

It's a mathematical problem for me.Now, once values reach 10X earnings, I think you start seeing things slow down. 

Like Albert Einstein said, "compound interest is the greatest mathematical discovery of all time."

Is what you say "mathematically" possible?

This pandemic was predicted and modeled mathematically for decades to occur either naturally from deforestation and human contact with rare animal species and insect species, or in the situation of COVID 19 from direct human manipulation, of viral genetics.

Find that answer and manifest that answer onto your website.I have turned ranking #1 into a mathematical equation. 1 + 1 = 2 no matter how often you do it.These are all people that used that equation to rank.