After running istick 30w and istick 40w on kanger sub tank mini rba coil 0.56 both on watts vaped at 16.5 watts doesn't seem to be any difference in battery life one is rated at 2200 amph the other at 2600amph any one else noticed this or have I got a bad one,the 30watt is 6 months old,i thought there would be affair bit of difference thanks in advance.