You're right. It's time spent and not work performed. Original comment edited.
However, in many professions being available for a given number of hours is often a major part of the job, and that means there will be a direct requirement to hire more people in order to cover the reduced working hours.
However, in many professions being available for a given number of hours is often a major part of the job, and that means there will be a direct requirement to hire more people in order to cover the reduced working hours.