OctoTable always takes your needs in consideration, and that is the reason why you can decide how you want to best manage your restaurant.
From the menu on the left-hand side under Configuration > General settings you can decide whether or not to activate the tab Ignore configurations for manual bookings (e.g. New room reservation not in service).

A) By setting this to Yes, you can manage manual bookings without taking configurations into account.
A couple of examples may be useful to better understand:
1) You can create a new reservation in a Room not associated with the service.
For example, I have two rooms, Indoor Room and Outdoor Room, and I have associated the Indoor Room with the Lunch service. By activating this option, I can enter a reservation for the Lunch service in the Outdoor Room even though I have not associated that room with that service.
2) I can place a 6-person reservation on a 4-person table.
B) By setting the option to NO, the system will enforce the configurations set.
Returning to the example above: if I wanted to make a reservation in a room NOT associated with the service, the system would not show the room in question as bookable.