Given the sheer amount of spying that goes on in this court, I imagine that this meeting up before the king’s bedtime is probably a regular occurrence. Probably Polonius could bring along a glass of warm milk with his reports. Maybe it’s a part of Claudius’ bedtime rituals. He gets jammies on, snuggles under the blankets and instead of a bedtime story, he gets the spying results from Polonius. Maybe the day’s report is what helps him settle in for the night. Once he knows what everyone has gotten up to all day, he can really relax and get comfortable for sleep.