Some things to keep in mind...
1. New rechargeable batteries (of any chemistry) usually require anywhere from a few to a few dozen charging cycles before reaching peak performance.
2. There's no regulation on how a manufacturer goes about claiming the capacity of a battery, I have no doubt that Hyperion's rating of 3,500mAH probably has a real-life rating more in the neighborhood of 2,700mAH...Especially at such a discounted price.
3. Testing while looping a movie seems like a good indicator. I'd only suggest also putting the phone into airplane mode (to remove the radio from the equation), use an App Manager to make sure nothing else is running and lock the CPU to a specific frequency (if you have SetCPU) during testing.
Even so, 160min vs 115min is about a 40% increase over stock...So 1850mAH increased by 40% is right about 2600mAH, which is right around the range of my #2 statement above.
IMHO, with this 3rd party lesser-known name and at well less than the cost of what the OEM battery costs at -supposedly- half the capacity?...Yeah, I'm setting my own expectations on the low side when I receive mine that I ordered yesterday.