Excellent question!! There are some "overhead" times that the scheduler uses to make the calculation:

For you, set Rotator speed, Guider Startup, and German Flip times to 0. "Go long" on the others to prevent time slot overruns. It's better for these times to be conservative (overestimated) since it will just cause the scheduler to be a bit less efficient. Too short will cause overruns and late starts (or missed fixed time slots).

In practice, do these critical runs in isolation as part of the final adjustments to the scheduler. Look at the Scheduler Engine log and ACP run logs to see if the estimates are conservative enough. To save time during installation, just go long on these and see later if it's ridiculous or not.