$50 a year gets you unlimited S3s and 6 S2s for your eligible riders. Parents get S3B1, unless traveling with the employee. If you don't have kids, they get better. There are some other details too. You also get 8 passes. They can be either RT or OW. Best to always purchase RT. You can always change it later. The cost is based on the distance they are going. ATL/LAX is gonna cost more than ATL/ STL. Only time it costs you more for family is traveling g international. PFCs and departure/arrival taxes are payroll deducted.
With load factors in the 90s, S4s can sit for days sometimes depending on where they are/going.