Your guess is correct, but you could make things work if you changed ticket 1 to LAX-PVG (nonstop) and/or ticket 2 to PVG-SYD (nonstop). There are 4 daily flights on the former, and 3+ daily flights on the latter (CA 175 operates on Tu, Th, and Su only). If you're weighing using cash v miles, LAX-PVG is usually a great value with cash, while PVG-SYD (even with a connection) usually isn't. If you do end up flying PVG-HKG-SYD, I suggest spending at least a night in HK because I've witnessed many sad faces from people misconnecting connecting there. The problem is, if you slot in a 4 hour layover in HKG, there's a decent chance that you'll end up wasting 2.5 extra hours in HKG, but there's also a chance that PVG/SHA-HKG will be more than 4 hours late.