Tax deductibility isn't determined by the security it's attached to, but the loan purpose.
As such that 100k would NOT be tax deductible if it was used to pay down PPOR debt.
The difficulty being with some lenders who cancel loan accounts as soon as they have a 0 balance, e la CBA.
All part of the process however in forming a finance strategy.
Same interest rate on loans with offset accounts? For the most part yes, though there are some lenders offering bargain basement offerings without offset accounts.
