I believe it's the "human median cut" introduced in c2.
one of the odd effects [visible] WC has more pattack than SwS (w/ less str and same weapon, no SC)
Since mystics have low CON adding +4seems like a hefty amount (also orcs mystics lose fewer HP w/ -con than fighters...) and it helps.
Thx for straight 'no':)
Though question still have to be cleared:)
I will give an example: the higher your level is the less chances to be stunned by low level mobs. Please keep in mind that CON usually is permanent stat (take aside tatoo) so landing stun condition depends also on smth else. What is this 'else'?