Max mitigation

[Koha]

I fail to understand some of my combat logs and would be grateful if somebody could explain it to me :

got 3 different skill hiting a tank : (I had no debuff of any kind)

AA hit for 40 (182 mitigated)
Skill 1 hit for 69 (405 mitigated)
Dot 1 hit for 40 (181 mitigated)
(all physical)

AA = 82 % mitigation
Skill 1 = 85% mitigation
Dot 1 = 82% mitigation

MAX mitigation should be 75 %, isn't it ?
I have 609 weapon skill, even with 5500 armor (tank with pots + armor talis) I should get a 71 % mitigation

Is there something wrong in my calculation or is there a problem ?

(I have a screen shot if needed)

[roadkillrobin]

Toughness is shown in these logs aswell. So its toughness + armor. And some spells get higher contr from stats wich means toughness is more effective against those spells aswell