Every couple of months I hassle my host as they don't update my stats for a few days, usually 3 or 4. Sometimes (like right now), its really important. I don't want to seem like a bother, but isn't that part of their job.
They are allowed to set the updates to whatever they want. It takes up a good chunk of cpu resources sometimes, so some hosts set it to a less frequent time so it doesn't hog as many resources. Mine update every night because that's how I set them to do it.
Of course, they do it when they want to do it, but all serious hosts update stats (at least) once a day. If the updates are irregularly scheduled, it is probably a sign that they do not have things under control. Jean-Luc
I had the same problem with my host before but i asked them to change it and they did because i'm one of their best customers (hosting tons of sites with them) Didier