Muzza, I'm not using the PE style of eating, but have used body composition monitoring scales since I started weighing myself about 3 months after diagnosis. For me the fat and muscle percentages can wobble a bit, and I think, but haven't tried to prove it, that hydration has some part in that.
For me, I am a bit hawk-eyed on my visceral fat. When I was trimming up, it was by far the slowest metric to reduce - partly, I feel positive, because although my scales will go up to a 150kg in 100gr increments, visceral fat is measured on a scale of 0-30, with <9 being a "healthy range".
Not sure if that helps at all.
I was part of a recent research study where, as part of an MRI scan, my visceral fat is measured, then calculated as part of a different study. I haven't had the feedback on that element yet, as the PhD student doing that work has a bit of a backlog. Very glad they researchers are getting as much s they can from data collected, and that hey are able to collect on an incidental, "whilst we're there" basis.
Needless to say, I'm interested to learn more about that when my calculations have been done. With as VF score of 3 on my scales I'm not expecting any surprises on it, but in all these things, we have to keep an open mind!