We never ride trains and my reading comprehension seems to have disappeared somewhere along the line. For a trip in June, I bought a Saturday ticket from Berlin to Neubrandenburg and initially selected one way. A price appeared and I then decided to go ahead and book the same day return -- the price stayed the same and I thought this indicated that it was an open use ticket that I could also use for the return trip. The "Use any time between 9:00 and 3:00 following day" also came up. We don't have a known return time that day. However, in doing additional research, I keep seeing entries that seem to say I still need to buy a separate return ticket. The train is an 8:47 departure, but the info also says that on weekends it can be used any time during the day and not subject to the "9:00" entry??