Disc/Technique/Photon Art Potency?

I noticed that while learning new attacks, that each one has potency. Is there a way to make the attack better per level, or is it a set value no matter what?

Potency is a set value at each level for default PAs.

When we eventually get crafting, Techs and some PAs can be customized. For Techs this can change their Potency, Charge Time, or various other number based things (though there is only a certain set of recipes for each Tech, and they are not all the same). For PAs (and some Techs), this will completely change their behavior in addition to modifying Potency and PP cost. In both cases there is an RNG factor where the new Potency can come out from a range of different levels, meaning that you will not always get the same Potency when you make thse customized PA/Techs.