HK fares during Sep school holidays

Planning on going to HK with the family in the Sep school holidays (depart 17th Sep) for 2 weeks and the cheapest fare is Qantas ($4,227). Should I book now while seats are available or will there be specials later on in the year? I’m conscious of most cheap fares is generally not applicable to the school holiday period and don’t want to miss the sale fares. If it was Cathy Pacific or Singapore Airline I would book without hesitation but being Qantas, would only go with if no other options.

We have 3 kids so want direct flights if possible (at least on the flight back) with departure times that are kids friendly as we have a 2yo. The Qantas direct flights depart @ 9.30am going out and 8.30pm coming back. For similar flights, Cathy Pacific cost over $6,000 now although they had cheaper ones just after Xmas with either 7.00am flights or stopovers one or both ways. Found one that was $2,800 but hesitated for 1 day and no longer available.

Thanks in adavnce for any feedback.