This is taken form a post made by a SW Staff member. It answers some of our mission payout questions:
Mission Rewards
The tokens and XP rewarded for completing a mission, is determined by a calculation that takes the following into account:
The number of plays the mission has had. As a mission gets more plays, the system becomes more “confident” about the average time taken, and pays out more generously. After 100 plays, the system has full confidence in the mission times.
The average time to complete the mission. In general terms, the longer the mission takes to complete, the bigger the payout. The system has an upper limit of 30 minutes per mission (i.e. if the average time to complete the mission is greater than 30 minutes, the reward will be limited as though it only took 30 minutes).
How fast the player completed the mission when compared to the average time. The faster the player is, the better the reward (up to 1.5 times the reward given to an “average” player). Likewise a slow player gets a small penalty, when compared to a player who completes close to the average time.
Note: If you change a mission by adding or removing a task, the system will lose confidence in the average time, meaning the rewards will be calculated as though it was a new mission again.