Was doing some testing on an EP Lizard in Cape Terrigan (Ninjutsu Skill 270, btw) just as I jumped on. Kind of rushed, and I haven't played NIN in a long time, so this may or may not be entirely accurate. Recently I've gotten a fix for NIN just for this. Don't mind the LS chat.
Ni spells with TP set:
Futae:
(Suiton for 127)
Ni spells with some MAB+ MACC+ and INT+ (Snow Ring, Omega Ring, Moldavite Earring, Denali Feet):
Futae:
INT, MAB and MACC were studied to have an effect on Damage previously, perhaps this boosts this further? Elemental Resistances are apparent.
Post more in-depth and elaborate testing here.