I had a Samsung 8.4 Pro before the GPad and sold it to a friend. He did the same video test and only lost 19%. I'm thinking of trading with him plus cash on my end. I really didn't like the Samsung but I need to get thru a whole day w/o having to connect my backup battery.
At this point I'm confused how others are getting the usage they claim. I've done just about all I can do aside from trying to find a higher capacity battery and modding it to work. I think I'll put the stock battery back in and eat the shipping and return fee and return the new battery.
I still am dumbfounded how my Sero 7 Pro lasts twice as long with a smaller battery