So I'm building a cavalier to hit hard with mounted charges, and I plan on getting rhino hide armor for that extra 2d6 charge damage. With spirited charge, I'm going to be able to do triple damage with my lance. What I'm wondering is if the rhino hide armor counts as a different damage source for the purposes of what gets multiplied. Basically will I do (triple lance damage) + (rhino hide armor damage), or will I do triple (lance damage + rhino hide armor damage)? I know where multiplication is concerned there are some things that don't multiply (like sneak attack on critical hits), so I'm just unclear.
The extra damage from rhino hide does not get multiplied.
as extra dice the rhino hide armor is not multiplied.
Multiplying Damage: Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results.
Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage. So if you are asked to double the damage twice, the end result is three times the normal damage.
Exception: Extra damage dice over and above a weapon's normal damage are never multiplied.