https://moosh.im/wiki/index.php/Beta_Program

That firmware is quite old (I have 1522204715). Fw-updating has its problems and might took several tries, so those are not forced anymore to those of us that do not use 10 minute intervals etc.

I get that the “Hz” setting means how frequently the instantaneous DC voltage is measured so as to figure the AC characteristics.
But what does the “samples” setting mean?
It just means how many of those dc-samples are taken in one go and then analyzed. For example, you need to allow mooshimeter to see a whole sine wave to calculate its rms-value, by keeping amount of samples large enough at the sample rate you have selected. You can check what mooshimeter really sees and uses as a base for calculations, if you go to graph mode -> config -> buffer mode. It then displays your sample buffer snapshots without processing.