idle power mode not working as expected

Hi,

my energy meter is working properly and it shows 17W in "idle" ,even when all devices (TV, digital converter) are disconnected from power.
During TV signal it uses mostly 23W and it goes for idle for 17W, even after removing optical cable.
When i turn on the TV the power goes to 23W again.

So, why it is using 17W when only the playbar is connected to power? (no WLAN, app closed)
What can i do? as its not the expected official consumption?
https://sonos.custhelp.com/app/answers/detail/a_id/260/~/sonos-power-consumption-when-idle

Regards,
Murrato