acquiring Puissant X with a spell

Okay, so Realms of Power: Faerie has within it a MuCo power to grant an individual Puissant (Ability). Throughout the book when powers are using a non-Hermetic basis for magnitude calculations, those deviations are called out. They aren't called out with the granting of Puissant abilities.

The takehome is, since Puissance doesn't really muck about with the Limits of Hermetic Magic then this is a reasonable ability to grant.

From there, you end up with the idea, why would there not be a MuCo(Vim, X) spell that grants Puissant spellcasting? The Requisite would correspond with the Technique and I tossed in the Vim Requisite because it seemed appropriate, but ultimately you end up with a low-level effect, maybe 20 or so, that grants +3 on your spellcasting with that Technique.

Not a rumbling game-changer, but an easily-acquired generally-applicable little boost that's probably worth the one season it would take to create such a thing.

Shouldn't it be a creo effect since an aspect of the character is being improved, rather than changed?

Based on RoP:F, it's Muto. One possible reason might be that Puissance is not anything inherent, and is akin to giving wings or gills.

Honestly, I don't know.