No, there’s no schedule for it. Since we cannot afford a dedicated server for the 3d bag, when we need the server for sth more important/urgent, we turn off the service(s). Usually they last from one day to a couple of days. However, this might happen max a couple of time per year. When you get a 502 error from the wfs/wms, then this is probably the case.
To be honest, if you want 100% uptime, then for the time being its probably better if you maintain a service for your clients yourself, based on the available downloads. In the future we might be able to offer a more reliable service, even for free.