Why does my PSU "vampire power" when turned off?

[CodeProto]

I was wondering how this happens, after connecting my PSU to a surge protected splitter it was using 0.01 amps when the button on the PSU was turned on, when turning off the PSU, it was using around 0.13 amps. How does it happen a turned off PSU shows a higher amperage usage than a turned on PSU (by the way, the computer itself is off, just talking about the PSU).

I am not sure if this is the right topic to post it on but I am not an expert and I am interested how this could happen, I don't actually turn my PSU off usually but I want to know how this happens.

[Kilrah]

Just shows that your meter is unable to measure such small / zero currents accurately. 

[CodeProto]

8 minutes ago, Kilrah said:

Just shows that your meter is unable to measure such small / zero currents accurately. 

I will maybe order a new meter as I will take your tip but I am not sure as it easily counts low power things like lamps and chargers very accurately.

[Kilrah]

Most meters just will not report anything accurate below a couple of watts.

 

0.13A at 230V is 30W so obviously that can't be for a PC that's off. 

 

I do have a meter that reports my laptop's charger as drawing 20W when it's just connected to mains and the other side isn't connected to the laptop, but it's BS since if the charger itself was dissipating 20W it would be melting itself. Another shows 0.