I'm not a CBS commish, but that line means this. If your commish retroactively changes your roster to activate certain players, those players won't necessarily be active for, say, tomorrow's games. It is just contrasting the fact that if you activate certain players for a future date, they will be in the active lineup for all days after that, unless you change one of those days.
Active- Players A,B,C,D,G,H
Bench - Players E,F
Active - Players A,B,C,D,E,F
Bench - Players G,H
Unless you specify the lineup for any dates after 8/17, players A-F will be active and players G-H will be benched. If you set the lineup for 8/18 as:
Active - Players A,B,G,H,E,F
Bench - Players C,D
All dates after 8/18 will have that same configuration. However, if your commish goes back and changes the lineup for 8/12, all the lineups from 8/17 on will remain the same. You need to make changes to a future date to do the "auto-update" as in the case of making a lineup change for 8/18.
Hope that wasn't too confusing, it might be....