Jass function:AddLightningEx, does not always work properly?

[Lookoverthere]

I have a spell that "throws" an enemy unit around the caster with a lightning between the two units to simulate a thread or rope. On the map where the spell was created the lightning works fine x,y, and z but on another map the z coordinate of the lightning is always off. Aside from terrain height differences everything else is the same. Has anybody else had a problem and if so what is a possible solution.