Xenon Damage Formula

You can't change weapons to determine damage formulas, they're not inherent to the class, they're based completely on the weapon (not just the multiplier). Going from Energy Sword to Umbrella changes your damage formula from Energy Sword's to 1H Sword's:

Energy Sword Multiplier * (4 * Main Stat + 1 * Secondary Stat) * WATK/100 -> 1H Sword Multiplier * (4 * Main Stat + 1 * Secondary Stat) * WATK/100
Where Energy Sword's main stats are STR, DEX, and LUK, with no secondary stats, and 1H Sword's main stat is STR, with DEX as a secondary stat.

My range is pretty high when I equip random stuff like daggers on my mages though. I'll go check on something that's not a mage real quick.

edit: range went 1441 -> 1571 with a sword equipped on Mercedes after I cast MW
1441 range with 68 str 1055 dex
1571 range with 71 str 1155 dex

1571/1441 = 1.09
71/68 = 1.04
1155/1055 = 1.09

So it's still using Dex as main stat and Str as secondary. Nvm it's using str as main stat, it's just that most of the range is coming from the secondary stat. So boosting the secondary stat by X% still ended up boosting range by X%.