So I went back to JP and see if I could Double Parry vs Sodam...and I did Double Parries vs Sodam here.
Welp, at least, with this, I could narrow down my problem with Double Parries in NA to 10% skill issue and 90% server(?) issue. Don't get me wrong; I could still miss my Double Parry here but I'll need a lot more practice to get it right in JP, which is something that I'm not planning to do since I'm pretty much fully focusing on NA servers and I cannot even do a single Double Parry in NA...
Good to know I guess, not that it makes me feel better. This probably also explains why I'm struggling so much with any-kind-of-ding-ding-ding things in NA, both in PSO2 and NGS; most combat stuffs happens on client side but I'm pretty sure that hitbox/parry/counter and JA/Perfect Attack timings are still very much dependant on server side.
Anyway, time to git gud in NA with Single Parries.
Kr1ze
Ship 4
Kr1ze's PSO2 Videos Playlist:
（C）SEGA
『PHANTASY STAR ONLINE 2』公式サイト http://pso2.jp
Timeline:
0:00 Quest preparation
0:58 Sodam
4:42 Phase 2
9:35 Phase 3
11:37 Quest clear!
11:52 Scoreboard, stats and equipment check