Never got an answer to my question in the preliminary thread so I'm reposting it here:
The skill tuning table says increased SP scaling on The Nomads Mirage skill. This skill does random damage and the skill description doesn't mention scaling with SP. Is all random damage scaled with SP? The in-game help says random damage is calculated from ATK and MAG.
Quoted from the in-game help on damage types:
"Some characters deal Random Damage which randomly picks from one of the above types [physical, magical, true], but any damage dealt will scale off both ATK and MAGIC."