I did some research to see how much of a difference that the difficulty level makes.
I used the tier 1 mission "Toy Soldiers" and the monster Scuttlebot to test how much damage and health the monsters deal and have, respectively. All I had on was a Spiral Sallet, Fencing Jacket, Iron Buckler, Bolted Blade, and Punch Gun; no trinkets or battle sprites. This is the data I collected using Notepad.
"Toy Soldiers (3-1)
Factory Floor (Depth 2)
Scuttlebot
Lvl 5 Spiral Sallet
Lvl 2 Fencing Jacket (Dmg Bns Med)
Lvl 1 Bolted Blade (Effected by dmg bns)
Normal
Monsters deal quarter pip of damage
Monsters take 3 hits to kill
Advanced
Monsters deal half pip of damage
Monsters take 4 hits to kill
Elite
Monsters deal 3/4 pip damage
Monsters take 5 hits to kill"
It seems that damage is increased by a quarter each time, and that armor/health is increased by a third each time.
-Pery
armor/health is increased by a third each time.
FYI it's 100% on normal, 150% on Advanced, and 200% on Elite.
It seems that damage is increased by a quarter each time
....
Quarter of what? From your values, it looks like the damage is 100%, 200%, and 300% for Normal, Advanced, and Elite, respectively. But these values were taken after defense. From what I understand, knights have twice as much base armor on Normal than they do on Advanced, and none on Elite, monster damage probably doesn't actually change, except for the composition of special to normal damage.