Zombie, I'm fully aware of the mathematics of PMs and read that thread when it was made...
Advent do have higher shield mitigation late game, but not in early or even mid game...however, they always have more shields and thus will always be more susceptible to weapons that bypass them...well before late game, you will commonly see advent capital ships or titans die to Vasari fleets (read: bombers or kanraks) despite still having substantial shield points -- the same cannot be said for TEC or Vasari ships (though I'm sure it occasionally happens if a Dunov or prog ally is involved)...
So, at stages where all factions have the same shield mitigation (early and mid-game), Advent caps/titans are dying with shield points left while TEC and Vasari caps/titans aren't...the subject has been hashed to death and the math shows that targets with relatively less hull points die significantly faster to PMs (though honestly that should be intuitively obvious)...
If you take away all the shield mitigation bonuses Advent can get, their ships will still die much faster to PMs than TEC or Vasari ships...it is not because the PM DPS is relatively higher against Advent (though it would be if they had shield mitigation bonuses) but because they have relatively less hull points (and armor) on their ships...
In short, even if Advent did not have any shield or culture techs to raise their shield mitigation, they would still be disproportionately affected by PMs...
PM's I don't think are inherently OP, case in point being the kanrak...when comparing upgraded LRFs, the kanrak is best against caps/titans but is the weakest in fleet battles, so it is more or less balanced...Vasari bombers on the other hand are OP, but more because of the base damage...kanraks have low base DPS per fleet supply because their weapon techs are going to give greater bonuses -- it only makes sense that Vasari bombers also would have lower base DPS per fleet supply because they also will get greater bonuses from weapon techs...
If Vasari bombers had their base damage nerfed, Vasari would be more or less fine in the TEC vs. Vasari matchup, but it still would have a huge advantage in the Advent vs. Vasari matchup...you can't make a general nerf to PMs that won't affect both matchups, so it is only logical that you give Advent bonuses that specifically help them block phase missiles...the culture buffs do not accomplish this and never will because they only affect the Advent's defense (the current values also are way too low)...only a straight bonus to PM blocking from the Advent shield techs will solve this issue...
I don't think it would hurt to change the VR PM tech to simply buff damage, not chance to bypass, but that is of secondary importance to nerfing Vasari bombers and giving Advent better PM blocking....