Thanks Duane and MoFoQ, I learned something too. So the Fluke deliberately gives you the peak value when measuring in DC mode? That’s quite strange.
Also, MoFoQ, sorry I wasn’t clear earlier about what I meant by buffer mode. What I was thinking was that you could turn the meter up to 4000Hz, 256 samples, then take a screen capture of buffer mode of the rectified output you’re trying to figure out. This way you could see the full waveform and see if the meter is introducing some kind of error.