I would guess there are two types of processing at work, which correspond with the two ways in which waitlists can be confirmed. Firstly if someone else cancels an award seat they'd booked earlier, in which case that is seat is automatically (and often immediately) reassigned to someone else on the waiting list without any need for manual processing. Secondly, when revenue management decides to release additional award seats for a particular flight (presumably after these have been recommended by a programme that monitors booking loads for various flights). That second category is something much more likely to require manual intervention, and so more likely to occur on working days in Hong Kong. I've noticed a lot of waitlists seem to be confirmed on Monday mornings (and percysmith's list seems to contain more Mondays than any other days of the week). Just speculation, but perhaps someone returning to work on Monday, and approving the various award seat release recommendations that have accumulated over the weekend?