Range of Orbbec Persee is less than 4m

Dear orbbec users,

I started to use orbbec persee with my own built software based on the nuitrack sdk, and according to my first tests, the range is not even close to the declared 8m.
Less than 4m what I could achieve in a total dark room.

Did any of you have the same experience?
Best,
Popesz