I have a bunk bed that is a Double over a Double. When I apply a bunk bed in the room, (VRBO) the system generates it as a Twin Bunk Bed.
Bunk beds are also available in Double or Queen. In which case I have the Double. Providing the right size would mean that 4 people could sleep in this bunk bed instead of 2. I could switch the beds to 2 Doubles, but guests need to know that it is a bunk bed.
Also, my sleeper sofa is Queen size pullout and not a Double. The OwnerRez system generates it as a double.
The bed options that OwnerRez offers, are the way they are because they are based on what is supported by the listing channels, which are limited. For instance, while in reality sleeper sofas do come in various sizes, the listing channels simply assume a sleeper sofa to be Double in size - there is no option to select another size.
This has changed. On VRBO it is now possible to select twin or double sofa bed. Writing to request this option be available in Owner Rez amenities.