I am not sure how to spell it out more clearly than what I wrote already.
Why do you think the SAP system should have nothing better to do then to run jobs whose start dates are in the past?
This is not a "catch up" race, if a job's start date was in the past, then its past.
Gone, over, finito, bye bye.
The job calender only works from here on out into the future.
Nobody cares for yesterday's news or jobs that were supposed to have started 4-5 hours ago.
But if you did *not* suspend your customer jobs, then they will run at the planned point in time - not matter how long you did shut down the system - as long as that point-in-time is still in the future, its that simple.