After seeing about 3-4 times i had to kill the mob about 1.2k+ times to get one bag inbetween bag drops during the time i’ve been farming it leads me to believe both drops might actually be a .1% chance each not 1% 
The variation of drops i’ve been getting are about these so far from the most i can remember, and each hour is about 78-79 kills for me.
4 bags - 1200+ kills each
8 bags - 6 hours
6 bags - 4 hours
4 times Back to Back Bag Drops
and the rest seem to be on average of about 300-500 kills each or so around there