Yes, I had read the Fee Schedule, MEL_Traveller, and I hope your interpretation is correct, but for me there is still some ambiguity around change and service fee waivers - especially as to how they specifically relate to
adding sectors to a booking multiple times via the Call Centre rather than just tinkering with the existing flight times, dates etc.
When I read statements in Qantas emails like the one below I sense an inference that the changes which they say are "free of charge" are specific and/or limited, and therefore that QF may choose to narrow their interpretation later when they see people taking up quite a bit of call centre time stringing together OW Awards with up to 16 sectors without paying anything for it. I prefer statements which explicitly address the circumstances I can see myself facing.
"When you use Qantas Points to book a Classic Flight Reward seat on any Qantas or Jetstar flight, you'll be able to
change the date or cancel your booking, free of charge until 31 January 2022.
^ That's for Classic Reward bookings
for travel up to a year away." That's QF's bolding.
I'll still go ahead and make a couple of bookings and see whether making multiple sector additions throws up any glitches but right now it's still a bit vague for me.