I have spoken to someone that works there and what they have said is that some agents handle in excess of 30narrowbody flights per 8hour shift.
It all comes down to how well they know the loading because what was told to me is that after a while you get the know-how as to how many bags,cargo can fit where. obviously each flight can have its deviations.
My buddy says they handle about 40 airlines and the margin for error is extremely low(under1%).
All in all I was curious about them because of a potential employment opportunity. What iv seen is good so far centralised load control.