Rain of Arrows DPS in PoB

Hey,

can someone help me with calculating the single target dps for RoA, please?

I never brought this skill to endgame, but i want to without relying on a second single-target damage setup like Barrage.

So my PoB is at about 330k dps and 22 AoE (using Conc. Effect). Im pretty sure the dps is calculated for 1 projectile. The skill fires 22 projectiles and claims that half of them will land in the centre (whatever that means areawise).

Does this mean that a big boss like Elder would actually be hit by half of those 22 arrows?
I saw people claiming that "human" sized bosses would be hit by 4 or so arrows.

While i guess that i will only get the real answer via actually playing to endgame, id like to hear of your experiences with the skill. Is there a rule of thump?

Been playing poison ROA pathfinder in standard for a while. The way the skill is worded is awkward, but I think it essentially means if every arrow had a target in its area then half of the arrows would directly land on a target. Far as I can tell from experience it does NOT mean half the arrows will hit a single target. From comparing my single arrow POB DPS to other chars and the relative length of boss fights, it seems like 4 arrows hitting a single target is about right.

Thanks!