You're missing the fact that you just bumped a four month old thread.
"Ok, lastly siphon life.
1.5 second cast time, 10 ticks 3 seconds apart, and 1634 damage. Each tick does 163 damage. It takes 6 ticks (18 seconds) for it to be more damage per cast time than shadowbolt, unless you had a siphon / shadow and flame build -- which would be odd."
TheOnly says that SL is a 1.5 sec cast time, but SL is instant cast. Is there something I am missing here?