Infraction: 6. Do not post unless you have something new and worthwhile to say.
Message to User:
This really isn't adding anything to the discussion. Please either do the math and then draw some conclusions, or don't post. Guesswork helps nothing.
I am not sure about fire, but for arcane the usual cast time for my char with optimized gear (14xx haste, couldn't get any lower) is about 1.3s for AB, which puts 2AB very close to the optimal time for VPLC to proc (2.5s ICD). Maybe this is more efficient than for fire.