Game Mechanics: Range not being calculated properly on Z axis

[Mouse]

If Im not mistaken, the range of a spell, should basically be a huge circular aura around you, extending the same distance on all axis. However that is not the case, the spell range is significantly botched on the Z axis. If you are standing in front of a mob, you can cast at lets call Distance X, which is out of the aggro range of a mob. However if you are above a mob, you have to come well within its aggro range, and you will get aggro LONG before you come into range to cast your spell. I think this is incorrect. Anyone know what I'm talking about here?


For instance, doing golem wand camp in CT, Im trying to lower down into the water to harmony the mobs there, but coming down I cannot possibly get close enough to cast without aggroing every single mob there. (This is on Red.)