Arm Cannon Not Properly Ignoring Racial/Size

Arm Cannon is not calculating correctly - it is including race and (almost sure) size mods at the moment; it should be[b] ignoring all reductions except DEF[/b] - as can be seen here.

This skill has two damage parts:
1. Is based on Cannon Ball equipped and Mechanic's stats, isn't increased or reduced by anything except Property, enemy [url="http://irowiki.org/wiki/Def"]Def[/url] is subtracted from this part of damage.
2. Is based on Mechanic's Attack power, ins't increased or reduced by cards or equips that affect damage in % (Hydra, Archer Skeleton, Thara, Beret, Horn, Alligator, Asprika, [url="http://irowiki.org/wiki/Blinding_Mist"]Blinding Mist[/url]...).[color=rgb(0,0,0)][font=sans-serif][size=3]Can acquire weapon's [/size][/font][/color][url="http://irowiki.org/wiki/Element"]Element[/url][color=rgb(0,0,0)][font=sans-serif][size=3] and has damage penalty dependent of Enemy [/size][/font][/color][url="http://irowiki.org/wiki/Size"]Size[/url][color=rgb(0,0,0)][font=sans-serif][size=3] and Type of Weapon used, also enemy [/size][/font][/color][url="http://irowiki.org/wiki/Def"]Def[/url][color=rgb(0,0,0)][font=sans-serif][size=3] is just subtracted from this part o(f) damage.[/size][/font][/color]

I did all testing with a Pile Bunker and a Cranial Valk Shield, using iron cannonballs. Characters were naked except for
A. +12 CEB - swapped on and off.
B. Cranial Valkyrja's Shield

In both cases - offensively and defensively - racial increases/decreases applied.
I can do further testing with Skeleton Worker, Archer Skeletons, Mysteltainn/Tirfing cards and the like (even TG if need be), but I am almost 100% sure that these will also affect the damage, which they shouldn't.

Please advise.