Deduct from Stock and Room out of Service both make a specific room unsellable. However, they have different results for your overall room availability.
Deduct From Stock (DFS)
If you set a room as 'Deduct From Stock' this will remove the room ID from the total stock for the relevant dates.
DFS rooms will not be included in the occupancy statistics
DFS rooms cannot be sold or allocated
Deduct from stock should be used for long-term out of service rooms - for example a room being used as staff accommodation.
If you have a 100 bed property with 99 rooms sold and 1 DFS room your occupancy will be 100%
Room Out Of Service (ROOS)
If you set a room as 'Room Out Of Service' it will retain the room ID in the total stock for the relevant dates
ROOS rooms will be included in the occupancy statistics
ROOS rooms cannot be sold or allocated
Room out of Service should be used for Short to Medium Term issues - for example a fault with the room or room renovations.
If you have a 100 bed property with 99 rooms sold and 1 ROOS room your occupancy will be 99%.