upgrading tower and traps

Ok i got hit with this question that i am not sure how to answer, since i cannot find a players manual anywhere for this game.

example: you have a lvl 23 monk, and you lay out a lighting aura. you up grade it 3 times. since your lvl 23 and cannot upgrade it to the 4th tier of what i call 1 star general. if your higher lvl toon upgrades it , does the power of that trap tower or aura scale up from the stand point of lvl 23 or would it scale up to the point as a lvl 40 toon lvled it 

the tower stats at all levels depend on whichever toon built it.

It's all determined by original builder, always.

Also you cna max out upgrades at level 22 afaik.