[iphone 4] Disable FaceTime to improve battery life?

FaceTime, one of the most important developments available on the iPhone 4, is the video call according to Apple, which works via WiFi and only two iPhone 4. The tests performed by our User Julian, and confirmed by us as the users of Apple's official support, however, appear active FaceTime significantly affects the battery life.

 But read the experience of our users:

iPhone 4 (firmware 4.0.1 since the first sync) and since then I've always had big problems with battery life that was never even remotely approached to data reported by Apple.
The first week performance marked the exhaustion of 100% with only 3 hours of use and 18 stand-by. The battery standby fell more or less than 3% per hour without being used. Strangely, even counting the hours of use saliva without anyone touching the phone.
Following various recommendations of the Apple support forums I did restore the phone as a new (and not back-up 3g above) and I reset the Exchange account that I use (google sync).
At this point the performance is improved and I got to 5 hours of use and 28 stand-by. The battery hours fell more or less than '1% per hour standby. But still far from Apple's statements.
And then ... the turning point!
Monitor Internet traffic on the bill I noticed tim access to times when I have not used the phone so I started keeping count Kb monitored traffic data in the phone settings. I then discovered that the iPhone 4 contiunazione accesses the data traffic in the background (ie without using the web applications that enable the connection), generating an average of 400 kb 100 kb downloaded and posted every hour!
After several tests with applications I discovered the cause: Face Time!
Disabling it data traffic remains frozen until use by the user. Even the counter hours of use has increased from only stopped when no one used the phone and surprise ... surprise ... the battery has stopped running out alone and so fast!
Now my phone marks 1 and 8 hours of standby + 6h use and the battery is still 50%!
Are three days that the text and finalemnte benefits are those reported by Apple.
I then immediately wrote a post in Apple's support forum:
http://discussions.apple.com/message.jspa?messageID=12184831 # 12184831 and I'm already getting positive feedback from users!
The battery problem is extremely diffuse and could not believe he had so little resonance.

As mentioned at the beginning, we tried disabling FaceTime and actually notice an improvement in battery life. Personally I do not lament the negative battery lasts well as that of our user, but improvement is always welcome FaceTime and off when you are out and you are not under WiFi coverage may be better advice.