Why is my iPhone shutting down at 30%?

I just replaced the battery and the phone is now shutting down at 30%. I tried to run it down further by charging it enough to get started and then running video and can't get it down further. (Tried at least 10 times in a row.)

I also see that this battery only reports a full charge capacity of 1336 instead of 1430 using iBackupBot. It makes me wonder if this battery is defective. I actually have 2 iPhone 4s' and replaced both batteries (from ifixit). The other reports a full charge capacity of 1400 and works fine.

So, is this a bad battery?

tia.