Sounds good up to the part where you are going to use your savings. I would "borrow" the deposit rather than using cash to max tax deductibility.
Curious to know why he/she suggested the portfolio loan.
Sounds like possible miscommunication, doesn't sound right.
As TheFS said shouldnt use the savings from offset, if not enough equity for the next loan... Pay down the PPOR loan with the offset funds and reborrow the funds for investment, thus tax deductible. Would of heard people call this debt recycling.