Elementalist "Convergence" question

I'm playing ball lightning and when attacking bosses I shoot off a string of them. Because of the Convergence ascendancy, when you hit a unique you get the 30% more damage bonus

Question: Do the balls in the air also get that damage as soon as the first one hits? Or is it only for new ball lightning that I cast after that?

Kind of specific, but wondering if I should shoot once, then get the damage, then send the volley? Or just send them all?

Since convergence also has large aoe radius modifier, you can test yourself by finding stationary unique target such as atoll map bosses (totems), shooting your projectiles near that totem, and see if convergence radius bonus disappears after first hit, causing rest of the balls to miss.