I don't know about your particular model, but my 3-years-old Panasonic
has a much greater "standby" consumption than is stated in the manual.
This is because it regularly turns itself on (silently) to check for
updates. As you have noticed, this consumes a lot more power. In true
standby the consumption is only 0.3W, but it most certainly is not as
low as that in "check for updates" mode.
What I have not been able to find out is how often it does this.
However, it is not just soon after turning it off that I notice clicks
from the internal relay(s) which I assume are changes to the power it is
using.
Fitting an energy meter between the set and the power supply, and
checking it when the TV is in standby" mode, will give you a better idea
of the true power consumption over time. Note, however, that energy
meters may give misleading readings where switched-mode power supplies
are concerned.
--
Jeff