[Anupam Goli]

From the Q&A posted here:

A10: One of our primary goals is to increase FRC team participation wherever possible. In pursuit of this goal, we feel that offering vacant slots to teams who want them serves the goals of FIRST and FiM better than leaving them empty. While this does give additional playing time to some teams, all teams who wish to play at an additional event are free to enroll in the annual lottery for these available slots. All teams have equal opportunity for these lottery slots.
Also, if we left these spots empty, we would be giving additional advantage to any team attending a partially unfilled event. Mathematically, the system is fairer overall if the events are all fully attended. We want all events to have the same statistical significance in our system.
We add events in units of 40 slots. Growth forces us to add events each time we add 20 new teams. Usually the number of teams/40 leaves a remainder of 15-20 spots open. We prefer to fill these for event balancing.