Just a bit more on this.
As I mentioned, I am currently looking at a OW Explorer RTW fare (in J) - so a DONEx. Using the OW planner, I found it very expensive - abt $15 for "five continents". (Interestingly, although you can fly to Europe on QF via Dubai ("Europe") and so not touch Asia, they still count Asia as a continent, so Australia-Europe-Nth America-Australia is 4 continents, not 3

.)
Interestingly, when I checked the fare tonight, I got a
slightly cheaper fare (only abt $400) compared to what I got a few weeks ago - so the 'sale' calculation is probably using a certain set of airlines/conditions.
My itinerary called for me to go straight to the UK, then bounce around Europe a bit, then to Bermuda, then Florida, then bounce around the Caribbean a bit, then to Sth America and back home any way I could. This is neither work nor holiday, so I'm quite price sensitive.
Anyway I put the challenge to my TA to do better. I figured that by only doing long haul in J and shorter hops in Y, it would bring the price down a fair bit.
Results:
For April next year, using a Finnair ticket for long hauls (they have great combo deals and QF SYD-SIN), and including QF SCL-SYD, it came in at $8.8K for the long hauls in J, and $4.3K for 7 shorter hops in Y (incl Star Alliance where convenient).
Using a Lufthansa package for long hauls (ditto good combo deals and SQ SYD-SIN), and a mix of *A and AA for the shorter hops (and going back to LAX to get UA back home) long haul J was $7.3K and shorter Y legs $4.3K.
Now, this was not final pricing, just indicative, and not being careful to select airlines with lower fuel fines etc, but the differences may or may not be significant, depending how you read them.
OneWorld - saving $2K by flying economy on 7 flights, some of them quite long (eg BOG to SCL) - although cheaper, I'm not seeing a great saving overall.
Star Alliance - saving $3.5K for not quite the same configuration, but similar outcome to the OW option. This is a saving where I would consider it.
Take-away.
Their 'sale saving' for 5 continents in J is $1,300 out of $15.6K; worth having, but I can certainly do much better by a TA doing some creative planning and sacrificing a few short hauls into Y. And I suspect they are a bit selective when choosing their 'normal Vs sale' comparison. For most of us it'll be less, maybe much less. Also, by doing the AY/LH long haul deal, I can probably get quite a few of the shorter legs on Award tickets, saving more.
Other ways to skin this cat as well of course.