Yeah, I’m aware of that. The DWM doesn’t update statistics every frame when latency is high… it updates them at the same rate (n-many frames) reported in the UI 
I’ve decided to just fill-in last known good values so that it operates at the same speed as the line graph for frametime.
SpecialK64.7z (7.6 MB)
From what I understand, PresentMon does the same thing. A lot of its data is not actual sampled data points, but just re-using last known values.