I have it fixed to an extent now. The item now properly drains in 10 uses. It was due to something in related to the problem in this thread: http://theindiestone.com/forums/index.php/topic/17062-question-isfarminginfolua-le-not-defined-for-operand/
I believe my item is still getting it's weight reduced to .6 from 2 instantaneously on the first use. Shouldn't it go down to 1.8 lbs? I am not getting the bag to turn into an empty bag right now, but I think that is something I have to add to the original item.
Furious_Monk's post in [Question] Drainable item not draining... was marked as the answer