Really do not understand your question ‘How much would the payoff be discounted.’ However, Here is what you have:
360 N 5% i/y $456.30 PMT $85,000 PV
if you sell the first 15 years of payments at a discount to yield 12% to an investor, you have:
180 N 12% i/y $456.30 $ 38,019.54
10% $42,461.96 (at 10%).
In 15 years, you still have 15 years of payments. This is what remains (in 15 years) that you would still own:
180 5% $456.30 $57,701.32
In any event if the home sold during the time of the 1st 15 years, there would be a discounted payoff that you would receive as you would still have a secured interest in the back half of the mortgage where you sold the front half. The longer it takes to resell, the more your payoff would be as that back grouping of payments would in crease in value the more it comes closer to a present value.
The other consideration is that if the new owner of the home defaults and the mortgage is foreclosed by the investor who purchased the first 15 years, you would have 1st right of refusal to pay them off and own the property outright again to resell.
That happened to me on a mobile home and land package where I sold the front 20 years of a 30 year mortgage. About 8 years later, they defaulted, the mortgage company foreclosed, called me and offered it to me at a $20k payoff. I went to inspect the property, and accepted the offer, advertised it for $29k as a handyman specila, sold it in less than 2 weeks, closed and pocketed $9k. When you sell a mortgage, NEVER sell the whole thing. The difference in the proceed of selling the whole mortgage vs. 15 or 20 years of a 30 year mortgage is only a few thoughsand dollars and not worth the possibilities of additional profits later on in the even of a sale or default.
All of this is covered in Jimmy’s book, Invest in Debt. Also, if you really want a special course, see if yo can find Jimmy’s cassettes on negotiating. Those cassettes made fortunes for me over the past 20 years.
Lastly, I would agree with Michael Q and my other colleages…don’t sell with no money down! EVERY deal I have ever sold with less than $3k down was a problem deal…and those were cheap houses…the more your down payment the more likely it will be a success.
Hope this helps.