I currently have 200k in offset on the OO loan since it is non deductible debt, however with the recent drop in fixed rate for OO at 2.29% would it be worthwhile to offset the IP loan instead? The IP loan's interest rate is 3.89%. Some quick calculations below: OO: $200000 @ 2.29% = $4580 IP: $200000 @ 3.89% = $7780. After deduction of marginal tax rate of 37% + 2% Medicare levy. I end up paying $4745.8 of interest. If my calculations are correct, I will be slightly ahead if I offset the IP loan instead of OO? Am I working this out correctly?