Each class can have a different version of any given arte. The different versions can have slightly different damage spreads and hit counts. There are like 5 different versions of Hienrenkyaku/Swallow Dance in RadiMai 2. And even though both the Brandish and Paladin classes are direct copies of Veigue, the Paladin somehow does just a tiny bit more damage with the same artes, as if Alfa System thought it would make a difference. Other little differences include how Caius has the best Shishisenkou/Beast in the game (wtf?), or how Reid does less damage than Lloyd with his artes (which are mostly identical), but Reid can equip axes to make him do much more damage than Lloyd's "power of 200" anyway.
It may be easier to reference what is listed on the arte lists for the classes in the second game. Most of the classes were unchanged between the games (only the Hunter class was completely redone), so most of the data should be similar. I can't guarantee that that's always the case, but it should be close enough and future editors can fix any errors.