It was with a Lvl 40 SSR Sword Master with about 2000 ATK and only flat increases, no RNG Procs. The Dmg was somewhere in the 2000s with only a small difference between the weapons. Infantry Supression might or might not interfere, I don't know.
Well, I guess we can't really solve this without more information on the formulas behind the system.
I'll just take your observations as a guideline, until I can maybe test this in a more "realistic" scenario.
Thanks again for your effort!