Sorry for delay.
MoFoQ – I realize now your phone is one of the ones that does not provide an options menu button by default. Some Android phones no longer provide it, so I’m adjusting the app to stop relying on it. I believe you can still reach the menu I’m referring to for “buffer mode” by long-pressing the square button. The reason I’m eager to see a buffer capture is that it will show you the exact waveform that the Mooshimeter is seeing, so we can verify that the meter is seeing the peak and RMS voltage you describe.
With the other descriptions you’ve given, I think the Mooshimeter is functioning properly. I think giving the mean value as the DC value is reasonable. If it presented the peak value as DC value, I would see that as misleading in situations where it’s measuring a very spiky signal.