Indoor Location -- extremly huge deviation for distance

Hallo all,

Can anyone help me? I have met a problem for the indoor postioning by using Estimote Proxibity iBeacons.
I bought 6 beacons and I tried to use them for the indoor postioning. But every time when i measure the distance between beacon and my smart phone through the App “beacon scanner”, it shows a huge deviation, e.g. when I stand 5 meters away from the beacon and the results from the app shows only 2 meters, when I stand 10 meters away, it shows 2 meters…

So is this a normal problem for the proximty beacon? Or it si the problem on the app side?

The hardware, iBeacons, I think they are of no problem, because I justed bought them a few weeks ago.
I would appreciate it, if anyone has an idea.

Thanks a lot for any help in advance.