Obscurantis bonus damage to projectile attacks per 200 accuracy not working?

Im swapped my rare helmet with Obscurantis to test that thing on my new foulborn Claws Int Stacker Jugg Lightning Strike.

Accuracy changes from 185k with rare helmet with ES/int to 181k with Obscurantis.

181k Accuracy with 1% increased projectile damage per 200 accuracy = 905% increased projectile damage.

Im tested both setups on different bosses(regular and Uber ones) and not saw a difference.

Obscurantis not working?
Or what?
Projectile part of Lightning strike should get this bonus?

Obscurantis has been used for projectile accuracy builds for quite some time, including LS.

What helmet were you using before? IIRC in accuracy stacker set-ups, Obscurantis was budget until switching to a rare helmet. Quickly using Ninja as a source, of the 1456 people doing LS of Arcing + Foulborn claw, 99% are using rare helmet. So while 905% increased projectile damage sounds better on paper, the other modifiers given up can offset that.

How much % % damage increase are you gaining from Obscurantis? If you're going from 4500% to 5400%, it's not going to be as noticeable as going from say 1200% to 2100%. But how much did you have beforehand with the rare helmet?

Did your testing sufficiently account for the lightning damage range from Stomriders? Enough high rolls in a row will highly skew the data.