My Monitors see and indicate immediate values only, what you see on level meters in Sonar (and other meters) is "slowly dropping" from maximum. So, if something was loud during short time, slow monitors just can not notice that, while Sonar monitors display the level long time after it has already gone. "Ultra" is still 1/13 of second, so it can also theoretically skip some pikes. In addition, in case the level has dropped fast and the drop was caught, it will immediately transfered to LED (that is now way to change that in my plug-in yet).
I do not think that 8 parameters Ultra monitor can produce any significant impact on your general performance, I have tested presets with many hundreds of such monitors on slow PC (which can not handle many DimPro presets), but I have not noticed any difference.
So, if "Ultra" is working for you, fine. Otherwise I can try to implement "slow drop" for level monitoring. Still, the "resolution" will be 13HZ.