CPU Package Power should be more accurate because the one under ASUS EC sensors is based on current value (Amps), which is reported with integer precision only.
On the other hand, the CPU Package Power value doesn't work in some cases (i.e. when SVID support is disabled), while the ASUS one should work in such case.
I have SVID support on auto and SVID Behavior set to typical behavior in the BIOS. I don't know exactly what SVID behavior means though. So CPU Power under EC Sensors is not a CPU Package wattage reading?
It's not exactly the same value.
CPU Package Power is measured by the CPU based on IMON/SVID. So if SVID is disabled it won't work.
The value under ASUS sensor is an additional measurement performed by ASUS circuits/EC, most probably at the VRM.