@Dan M.
I’ve done this calculation a number of times and thought about paying off my house. For me and my payoff amount and interest rate I decided to refi and gained cash flow that way.
If I were in your situation I might have paid it off. It’s a pretty decent guaranteed cashflow/expense reduction for only $70k and no risk.
At this point I get excited about adding little bits of long term cashflow because that’s what pays bills and keeps me from having to use cash or investments for income.
Actually I’m pretty sure I would pay it off. But then I don’t know your whole financial situation, but my favorite real estate investor Bruce Norris says, he sleeps a lot easier with a paid off house.
I sleep easier with low expenses, which is pretty similar.
One last thing, don’t forget the ordinary income taxes you would have to pay on that 11% loan you would be funding.
Good luck with it all, it sounds like your are in a good overall situation.