There is a difference between a room type and a rate. A room type reflects a physical room. A rate reflects a varying price for the room type. E.g. a „double room“ (room type) can be sold for 50$ (rate A) and 75$ (rate B).

Please make sure that different offerings of the same physical room are set up as “rates” in the booking channel, not as different room types. Otherwise the channel will believe that there are more rooms than there actually are – which can result in overbookings.