I'm hesitant to introduce a sequencer into testing because I believe sequencer timing is independent of hardware timing. Since PC software is layered, and calling standardized APIs I think we can assume hardware performance as independent from sequencer performance. I do agree that sequencer latency is part of the sum of total latency. Is this assumption correct?
In documenting these, I think it would also be helpful to identify for PC which Timer each interface uses.
I saw a tool last week that would test drift and identify which driver to use. Does anyone know what I'm talking about? I can't find it now.
the app is miditime.exe
found here
Parapoetica: PC MIDI Timing and Nuendo