I have yet to travel, so no idea about the ODU situation, but the availability beforehand is actually refreshingly user friendly compared to the QF lottery approach. The proviso here is that you have purchased an appropriately upgradable class fare.
As per my previous post (which Lindsay cross referenced), things are even better when dealing face to face with some of the office staff. Having had a good discussion with them, we purchased fares which were (from memory) H basis - which came in about 50% dearer than the cheapest available at the time - but were upgradeable.
As soon as they were ticketed, then got most of the sectors confirmed as upgraded to I (Business), and even got the last sector waitlisted for the upgrade, which then cleared later. Now that I refer to the actual document, rather than memory, the subsequent change and reissue of an upgrade a week later (after another waitlist loop), after change of plans, cost a total of US$20pp - so quite reasonable.
Interestingly, although I class is used for the upgrade, it comes with the "full" 30Kg J baggage allowance, unlike the discount D class MH is offering at the moment - which has a lower baggage allowance. The only thing you don't get is the limo pick up and drop off - you actually have to pay for a J class fare for that!
For reference, in April this year, we paid approx A$1450 pp for the H fare BNE-KUL-xLGK-xKUL-BNE, and have all sectors upgraded to business (the fare is exactly the same as a BNE-xKUL-BNE return, the trip to Langkawi is effectively free as far as flights go - accommodation is a different story
). The difficult sector for upgrades is KUL-BNE. Seat pre-allocation is available for everything other than BNE-KUL (local airport control, and connected with the fact that the aircraft actually flies KUL-SYD-BNE-KUL).
