Good luck with this experiment, will try to buy the $100 HBD bond soon if it still there.
I'm curious if I'm getting it right you mean to invest HBD and make profit to pay 10% premium - right?
Sounds like a Good idea to bring some liquidity from outside.
You invest 100 HBD, wait 90 days, get 7.5 HBD extra (total 107.5), instead the 5 HBD from the regular HBD savings.