I know I'm late by a year or so and everyone moved on to feydark paladins and bards by now, but I only see two shots hit dummy either doubleshot % is 40 or 60+. This might be some bug after recent updates, but surely even with an actual 15% ds you'd have extra shots 1 out of 6 attempts.
I'd like to see more ppl confirm this.
Fix your goddamned game, SSG.
Edit: Thanks guys for correcting me.
Update 49 changes:
Prior to this change, Doublestrike gave you a chance to make multiple attacks. Now it gives you the change to do extra damage with a single attack. (This change was made to reduce server lag.)
The exceptions to this rule are Repeating Crossbows and the Inquisitive Dual Crossbows style. They still fire 3 or 2 full projectiles (so you'll still see 3 numbers or 2 numbers, respectively). However, they still have Doubleshot penalties of 66% and 50%, respectively.