Each aircraft might have different rules on how long you want the tail to be away from home before forcing a double rotation. In each pricing profile under Quoting rules you can add how many nights you allow your aircraft to stay away before forcing a double rotation on your round trips.
The double rotation will always be forced if it's the least expensive option, regardless of the number of days you will put in. To determine if stay on ground or force a double rotation the system will look on al line items in your pricing profile. Fell like overnight cost, parking fees will not be charged if your destination is one of your multiple home bases.