pathfinder 1e – How exactly Power Attack and critical hit works together for 2-hand fighter?

I tried to follow the rules and check FAQs but now I need a help:

I got a 13° liv THF (two-hand fighter) and 6° liv Aegis (BAB=19) and 5° Mithic tier, with Power Attack and Mithic Power Attack (but not obviously Greater Power Attack) and 34 Strength+Brawn (+12 mod), here are damage stats as I supposed:

    12x1.5= 18(THW) 
    +3(Weapon Training) 
    +6(Weapon Specialization+2, Greater+2, Mithic+2) 
    +4(Magic Weapon mod) 
    +3(Improved Damage from Astral skin customization) 
    +1(Psionic Damage from Astral skin customization) 
    +1(Psionic Weapon feat) and 
    +24(Power Attack,Mithic) = 60 for 1st attack and 66 for iterative (due to Backswing)
    and then add  2d6 (Weapon Damage)

Now the question is: Whats happens with a critical hit (x2 multiplier) on each point?

  • I’ve found many question and I read not enough answers about it so I fall in chaos each critical hit (no more a great pleasure but a trouble)-. I understand “I can multiply x2 only the dice, so 2d6+2d6+60 and 2d6+2d6+66 for iterative, but I’m really not sure.

and due to

Greater Power Attack (Ex)
At 15th level, when using Power Attack with a two-handed melee weapon, the bonus damage from Power Attack is doubled (+100%) instead of increased by half (+50%).
This ability replaces Armor Training 4.

then another question regarding Power Attack and Critical hit is:

Whats happens at 15th level for THF archetype and Power Attack change to Greater Power Attack, to each point on a normal and on a critical hit?

Thanks