Spells: Harmony broken?

[Droog007]

15 seems too big. The static mobs just past the 2nd bridge in KC look to be almost exactly 15 units apart. Going from recollection it should have been plenty far apart for harmony to work. Any chance we're misinterpreting how this 15 number figures in?

The way I remember it, harmony would only get adds if pathing took them pretty much right over the top of the other.