A people directory describes who can do the work. Desk Staffing stores skill proficiency separately from grade, office and rates. A senior grade doesn't prove proficiency in a particular tool. Read the required skill and its level before treating a job title as a match.
Use profile changes only when you have evidence for the change. In these exercises, a manager has supplied a verified update and the task states exactly what to enter. Existing skills should remain when you add another one. A blank skill is different from a recorded low level: neither meets a higher requirement, but the first may need a profile review. Rates describe scheduled economics, while the target describes the expected utilization percentage. Keep those fields separate so a reporting fix doesn't accidentally alter capacity or proficiency.