Is this current clamp meter measuring correct according to its specs?
You appear to be assuming 100 % efficiency in the power supply. If it is a linearly regulated supply, it will be well short of this. Even a switchmode might be only 70~80 %. The other thing to take into account is the power factor of the supply. A normal transformer/rectifier/capacitor supply may have a power factor of 0.66, at a guess. This would mean that the product of the input rms voltage and rms current will be about 50 % higher than the real power delivered.