A lot depends on what smoothing you set to rhe display. In the case above, I’d assume it’s the same, so the difference is real.
There will be smoothing the is in-build to the PM, and there’s nothing you can do about it. It’s likely different companies deal with that differently.
There’s always threads on here where people complain about “jumpy” power, because it’s the first time they’ve seen it with the smoothing turned off.