So, during the day, your agent is busy calling publishers, talking to editors, working with writers, looking at contracts, and doing all the things that agents do. S/he goes home in the evening, eats dinner, spends time with the family, and does all the things that people do. Then, at night, after the house is quiet, or maybe early in the morning before everyone gets up (depending on time differences), s/he gets up and goes and spends some time catching up on e-mail -- reading, sending, responding.
I fail to see the issue.