If I had to guess, I'd say those new folders are a direct result to the "update" to the backups that you are changing. I never change my backups. If I have new data, I just create another backup and delete the previous one. If you start messing with backups, you will inevitably corrupt the backup which defeats the purpose of creating the backup in the first place.
After looking up CrashPlan, I see that it's an online storage backup service that one has to pay for. Depending on the plan you have, I see that there is an unlimited amount of storage. If that is the case, then I would create daily backups.