I beleive that PS reduced the chance of glancing and the damage that glanced attacks do.
This is opposed to wpf's advantage in higher weapon speed.
So you have to be more precise with agility builds but it is easier to be precise. Extreme ath builds can put out really high dps due to speed bonuses but they dont work as reliably as you would think you have to be moving forward to get the most from them not by just spinning.
Myth, entirely. Glances and bounces are based on the final damage for the swing. PS indirectly affects the chance of glancing by multiplying your weapon damage by 8% per level and thus increasing the amount of damage you will most likely be dealing to opponents. If because of your opponents armor, you do 0 damage, you bounce. 1-2 damage, you glance without interrupting your opponent. 3-8(?) damage, you get the glance sound, but it still interrupts your opponent. (Not 100% on all of these numbers, but that's basically how they work).
To maximize a speed bonus you have to be moving with your opponent. So for horizontal swings, you don't want to be moving forward, you want to be moving left or right depending upon the swing direction you use. Furthermore, your opponents movement also plays into your speed bonus. Moving into someones swing always increasing the speed bonus of that hit. It's not a matter of simply moving forward or backpedaling.
