I made some tests with PPK-II in source meter mode by connecting a load resistor in series with a Fluke 8846A ampere meter to the PPK output. A also hooked a GW Instek GDM-8351 voltmeter in parallel to the PPK output.
Here are the results:
The PPK is out of spec around 500uA. From time to time, while changing the output voltage up and down, those red values suddenly got much better, in accordance with the +/-10% specified max. error. But I couldn't figure out what exactly makes the PPK suddenly jump in/out of spec. However, most of the time I observed the large errors from the table above.
Given the described behavior, I suspect a FW error in range changing logic. Are you aware of this? Can this be fixed in a future FW upgrade?