Coming back to my question earlier I've just come across this article:
How to book a long stopover with Qantas Points
It is my understanding that because it is a transit of <24 h (by 5 mins in fact, just like 2 of the examples in the article) then indeed it should not price as flight 1 + flight 2. I've gone back to play with the multi-city tool and today it seems to be co-operating. If I select flight 1 as the CX flight and flight 2 as the CX flight, it indeed caps at 182.9k. However, if I select flight 1 as CX and flight 2 as AY it comes out at 233.4k... (btw the AY flight departs ICN earlier)
You'd probably guess it's because of two different airlines but according to the article it should be fine as long as they are using the same table here:
https://www.qantas.com/en-au/freque...rewards/tables#partner-classic-flight-rewards
So I'm still not sure what's going on
EDIT: Realised the new tester flights I was looking at are different to initial query but dilemma remains the same they are
flight 1
SYD-HKG-ICN arrive 22:25 (CX)
flight 2 next day depart 20:05 ICN-HKG-FRA (CX)
OR
next day depart 21:50 ICN-HEL-FRA (AY)