Just organising a third back to back exOSL DONE4 RTW.
I’m fluent in Expertflyer, routing and availability; but I’ve accepted pricing rather randomly and am wondering what steps other RTW afficionados take to calculate and review taxes and charges.

From OSL we normally head to Australia with or without an Asian stop, normally using QR although we’ve also been AY via HEL. I’m hearing that QR. is quite heavy on the charges not just for that leg but for elsewhere in the itinerary as taxes vary by ticketing airline not just by route. Is that correct?

Other that the slow and tedious route of having AA’s RTW desk price different scenarios (it seems to take 20 min on the phone per scenario with their very manual method) or the bug-ridden oneworld tool, are there some online tools I should be using to explore impact of YR/YQ?

You unfortunately can't test 100% accurately on the tool since QR can't be your first segment. Just for testing purposes, I might try OSL-MAD with a stopover, then do the rest of your itinerary as you'd do from OSL. LHR isn't a good one for testing because of APD and you might attract some stray BA YQ, and QR doesn't fly their own metal into HEL, so not sure how that affects things since the tool would only show HEL-DOH on an AY code.

I don't think QR has the giant fees that tend to get rumored around here. I built a QR heavy ex-CAI during the sale and wasn't paying a significant amount more than others posting different itineraries. I was also told by QF when I did an amendment that CAI-AMM-DOH-CGK (RJ, QR, QR) had higher YQ and taxes than CAI-DOH-CGK (QR, QR), and that difference nearly offset the entire change fee.

Just my own anecdotal findings, the ones that may increase YQ more than others, BA, QF, CX, and MH. Having said that I've seen some others post itineraries with BA coded TATL or to Asia that didn't get hit with a huge YQ, so YYMV. As far as I understand the ticketing carrier definitely matters, so those may have been QF ticketed and didn't carry the same YQ implication for BA codes that an AA or BA ticketed itinerary would have. I've also come to an understanding that it's bad to have QF codes unless it's an ex-Japan itinerary (where YQ doesn't matter).

I think you are better off engaging a travel agent who has RTW booking experience. I realize that's not an online tool but it would meet your needs.

Just to illustrate how much difference YQ can make, today AA priced for me DONE4 OSL-xDOH-BNE-NRT-YVR-SEA-LHR-OSL.
A very helpful AA person spotted from experience that the Australia-Japan segment had high charges. By changing from QF BNE-NRT to JL SYD-HND, the fare dropped by $921 per person!

Interestingly I also priced a BA-ticketed OSL-LHR-HND-SYD-YVR-SEA-LHR-OSL to see whether the above QR-ticketed itinerary was attracting unusually high YQ. There was only about $100 difference.

These YQ costs are a real mystery to me.