I'm pretty sure it is

Have you ever tried stacking up multiple (2-3) levels of learning and starting the bossfight at lvl2? 10 levelups are guaranteed in a row, but with luck you can get even more.
Other methods can get you tons of bonus xp as well, but none let you set up 10+ dings. Also in VT Vicious most casters would struggle to consume every bit of popcorn, but not this one.
Being locked into TT is not a worry, once you reached the required amount of learning you can leave him and join a true spellcasting god.
Picking up TT's boons will net extra gold btw, good for buying additional items or potions.