Power Supply Efficiency
The efficiency and the power factor are not related at all.  The efficiency is the resistive input vs the output.

The power factor is most likely due to distortion in the current waveform and you have to be sure that your instruments measure RMS current and voltage and that the power meter can work with distorted waveforms.

Most quality switch-mode power supplies are power factor corrected as well and will not exhibit such a bad power factor.  Even linear power supplies distort the current due to the input rectifier and capacitor.