The Schedule in 10,000ft is designed to be the overall plan of record. While you can change the scheduled plan as projects and priorities change, it should always reflect the way you want projects to occur. Assignment updates on the schedule flow to time sheets, however confirmed time (from time sheets) does not change the schedule. This gives you a baseline for comparing actuals (from time sheets) to the plan (the Schedule).
Because the schedule is the overall plan, it is not impacted by any assignments or hours your team tracks ad-hoc (i.e. Sick time, additional projects to which the person was not originally assigned). All of this data is available in reports, but to weigh the actuals against the plan we preserve the schedule as the original plan of record.