90-91 i collected treasures that gave resources and then dumped them all in xp potions and began to clean up shadowmoon valley while also doing bonus objectives, after shadowmoon i went to gorgrond and did the same thing and then to talador for a bit before I was 96 and went to quest in arak until I was 98 when I picked up my artifact and went back for the last few levels. Overall 90-100 took like 4 hours.
I'd rather not have to manually re-do all the settings for all my addons in-game unless it's absolutely necessary (since I don't have memorized what the exact settings are I use, so I'd have to take screenshots of them all and then remake the settings to match the screenshots). So I'd rather get some more input about this problem before I try troubleshooting it that way.
Also note that power leveling is sometimes used to refer to paying someone else to level your character to cap as fast as possible (i.e. they power level for you); a distinction used by Blizzard is to refer to the paid leveling as "power leveling service." This behavior is against Blizzard's Terms of Service. Power leveling yourself, which this article covers, is perfectly acceptable.
All I'm saying is that Blizz destroyed Levelling in my opinion. Having the option to get it all out of the way so quickly was a good idea, while still having the option to clear it all like one normally would. WoW is a game that's meant to have options, and ours has been severely reduced to 2 options; "Heirloom On," and "Heirloom Off." They even killed RaF exp gain and it no longer stacks with Heirlooms. They even killed the SoR for no reason at all. Feelsbadman.