It does seem to occur a lot more in the wee hours. Backups would seem to jump out as the main suspect. I can't understand why incremental backups of files and databases would create so much load. Maybe they don't have a San and are getting network congestion. It all seems quite unlikely for a hosting company as it's fundamentals.
Opinions are like A**holes, Everyone has one. Some people seem to have more than one though which is a bit odd.