The part you need to understand too, is that the Zygor addon doesn't use an App like TSM to update many times per day your auction value. When i bought the gold guide i remember that i didn't understand much either, the results were random and from items i can't make much gold with. It just scans the auction house based on their most recent value update which can be days and days ago.
A few years ago a wow promotion came out that gave you a FoS for leveling a character from 1 to 20. So i started leveling a Horde rogue since i'd never played Horde (and i've played since vanilla), and the fun I had experiencing the "other" side was super fun and nice and I actually saw a lot of cool stuff and actually sorta-kinda got that old "vanilla" feel of exploring things for the first time.
If you want to get rid of all of registries left on the program removal and don't want your Windows system is fill with redundant registries that someday may affect the system performance, you should perform a registry scan and clean with a sophisticated registry optimizer, it will help you clean all the useless and corrupted registry files on the system.
I only subscribed about 2 days ago after coming back to WoW after 6 years. The game has changed so much since I left right around the Cata release. I decided to start fresh on a new server. I still had all my old links and logins to places like Curse, WowInterface, etc. Loaded up all the addons I had favorited years ago (of the maybe 1/3rd that were still maintained). Got to level 20 in a few hours of playing. Had to look a bunch of stuff up.