Mana usage modifiers.

So today I'm only using 49~50 mp for every cast. I also don't even need to have 60 mp to cast lightning rod at r1, which is completely out of character for magic.

I also highly doubt it's lag that makes me use significantly less (but not as significant as other spells) mana. My response time from the game is pretty on point.

UGHHHHH, so with my druid, it uses 50, with my S6 hermit, it uses 50, with my clean trinity, 52. Maybe it's a magic attack thing? But those all have way different magic attack values.

So I only need 46 mp to cast lightning rod, but it uses a bit more. Does anyone else have differing mana charge threshholds at r1?

Lag would make you use more, not less, indicating that masteries and INT factor into the cost. Latency can vary greatly across even a short amount of time. However, with a higher latency, other users may find they use significantly more than they should since SOMEONE decided it would be cool to drain across time instead of simply subtracting fixed numbers.