Currently Chaos Storm changes only once per reboot making it insane xp if you are lucky enough to catch it at a low level and have it go up to a high level, chaos ball changes constantly.
Why not instead have chaos ball (these #s just pulled from my ass but still work as an example) randomly change between level 7-15 or whatever, but only trainable once you get to the middle point (11 in this example).
Because xp doesn't increase linerally with level this would still be overall give better than a regular level 11 spell.
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If you say plz because it is shorter than please, then I will say no because it is shorter then yes.