How many hours are you currently selling?
No I mean, why not look at selling your hours (not property) at a higher price? Selling is the last option to ever be considered.
How long would it take to knock over a loan?
What's stopping you from selling more of your time and/or selling it at a higher price to increase cash flow?
What if the IO payments allowed you to hold another $500k IP...what would that IP have grown in value to over those 5 years compared to your $40k ? A lot more I'd say.