On separate tickets QF have a policy of not interline to other non oneworld carriers.
However, AS is a partner airline for QF and they might check any luggage through.
Having posted that, the main difference ois that that if the luggage is checked through you have more time to catch your onward flight as you'd redeposit it before leaving TBIT, otherwise you need to lug it to T6 and recheck before AS luggage check-in closes (8:05am?).
This would be the process:
- At MEL, check bags through to LAX (or PDX)
- Fly to LAX
- Disembark Aircraft
- Walk through the dungeon like corridors to TBIT immigration
- Queue up
- Be processed by Immigration
- Collect bags
- Queue Up
- Proceed to/through customs processing
- Head up ramp
- If bags are tagged to PDX look for signs for baggage "re-deposit" and re-deposit
- Head outside and to the left a little for the "A" bus stop.
- Wait for A bus then board
- Exit bus at T6 and head up to departures
- If bags only tagged to LAX, recheck luggage
- Head through security back airside
AwaitRush to board ongoing flight ...