Unless of course you read this change as if you must now choose which attribute you want to increase for each subject you cast the spell on. That you can't stack the same spell twice to increase two different attributes on the same subject ;-)
That is indeed another houserule I use for this spell

Mostly because mages can easily make most drain values a non-issue with Focused Concentration 2 and two instances of this, but also because I think that flat Attribute Boosts should be the strong suit of Augmentations and Adept Powers. Limiting the spell to one instance per target while keeping its flexibility makes it a bit more of a situational choice instead of a fixed set of 2-3 "Pseudo-Augmentations" that the mage activates as a part of the breakfast routine.
(Alternatively, I even toyed with some kind of time limit. Since your magically push the targetīs body and/or mind beyond its limits, the effect may start to strain after a while, and even quicker with multiple instances. Just a thought here...)
Perhaps it no longer make the subjects glow....
That
could be the intention here. In that case, Iīd definitely want a stronger, more more visible version! Hiding a behind a glowing shield is a very archetypical magical effect IMO.