i had not really stopped to analyse it but as my first run through I was trying to recreate a favourite character of my and ranger wizard and while I cannot get her stats (point buy) I just checked and she has 3 level spells despite being only Wiz 3.Huh. Now debating MCing Gale.
No, it's a Larian Homebrew to ignore that restriction. They upped the cost of Quicken to 3 Sorcery points to compensate ... but I've still managed to cast three Fireballs in a round (previous round drank a potion of speed, so I've 2 actions and a bonus action).