When I have been in my largest airport with over 35 medium stands and four runways, staff often only arrive at their designated stand long after they were scheduled to.
For example I have tried adding more staffrooms to reduce the distance they have to travel though often airport staff, for example, do not come from the closest staff room, and instead come from far away meaning that they can sometimes be upwards of an hour late to stands.
I feel that the game should have some sort of way of calculating how long it will take for a staff member to get to their designated spot. Also the issue of where the staff come from should be fixed to make it so that if their is a staff member available in the closest staff room or area of the terminal, they should be allocated to that job.