Current integral is not accurate?

[t-moe]

I'm trying to use this library with my PPK2 in order to calculate the total current consumption of my device, by integrating the current samples. In order to integrate the current samples, I've slightly modified the library (fork: https://github.com/t-moe/ppk2-rs), although I think this is not relevant for the problem I describe.

Calculating the integral works and gives me some number, but the number is way off, when comparing it to a 2nd ppk2 running alongside with the original GUI. E.g. when measuring over 20 minutes, I measure 57 Coulomb with the library, compared to 46 Coulomb with the original GUI.

Did someone run into a similar problem? Could it be, that the device is configured differently when used by the nordic GUI?