I dunno what numbers you're looking at, but the ratio of Full Thrust to Phlebotomize ticks is ~12x in-game. If you're comparing HT+Dis Full Thrust v HT+Dis Phleb, then the difference will be larger, since the Phleb dot ticks aren't piercing damage and thus aren't boosted by Disembowel. Potency scales perfectly linearly. There's RNG, of course, but the ratios are consistent, according to potency amounts. You also still don't need a parser to see these relationships. I sure didn't use one to test it out and figure out that potencies scale linearly with damage. (Since I was playing on PS3 when I did these initial calculations back in 2.0-2.1)
It should be /.9, if the game works the way the tooltip explains. It decreases piercing resistance by 10%, it doesn't increase piercing damage by 10%. These are different statements. Just because other people do it one way doesn't necessarily make it correct.
For the record:
x1.1 = x11/10
/0.9 = x10/9
Those numbers are different by 1/90. Doesn't really make much difference, except that dividing by the 0.9 is more accurate, assuming the game works the way it states in the tooltip.
This is getting a bit off-topic. The point still stands I didn't use or need a parser to calculate the numbers that give you an optimal rotation for Dragoon and Paladin. I haven't bothered looking into other classes yet, since those are my only two 60s, so no other ones matter to me at the moment. You don't need a parser to discover the skill floor for your class. You do need one to see how you're progressing toward the skill ceiling. It's really really obvious if a player isn't at the skill floor yet for Dragoon, at least to my eyes and ears. I've been playing the class since 2.0 beta phase 4. I know the sound effects and animations for all the pre-heavensward skills like the back of my hand. If someone isn't reaching that baseline plateau it is *painfully* obvious to me.
And if someone is at or above the skill floor, there's no real reason to be a dick to them, because at least they're playing "properly." If they're below, that's cause for you to offer constructive criticism and back down if they get offended.
The problem isn't parsers being illegal, it's players being too pigheaded to admit that they're doing something wrong. Hell, I've even had players respond with "So? We still cleared." after I tried to offer advice on how they could play Dragoon better because they were dealing about 50% of their potential. Maybe that would be fixed if they could see their numbers. Who knows?