Changing team split settings on a service type affects ALL service plans of that type (past and future). This article goes over how the system handles splitting and unsplitting teams which have assignments and/or needs.
When a team is split, the system will create a separate "sub team" for each service time on a plan. If there are no service times on a plan, then the team will not appear for scheduling until at least one is added. The split is done as folllows:
The number of volunteers needed for a position is divided evenly across each service time (rounded up). For example, if originally 4 greeters were needed and there are 2 service times on a plan, then both times will need 2 greeters after the split. Similarly, if 4 greeters were needed and there are 3 service times on the plan, then each service time will need 2 after the split (i.e. 4 / 3 is 1.33 and rounding up makes it 2).
Scheduled volunteers are assigned to the split teams which match the times they were originally scheduled for. Any non-service times they had are assigned across each split team they are on. The status for each assignment will match the original. For example, if their status was Accepted, then each of their assignments on the split teams will also be Accepted.
If the team was set as an assigned team on a plan time, then all the split teams will also be assigned to that same time. The only exception is for service times. Since splits teams are already meant for a specific service time, having them as an assigned team to that same time is redundant and so those are removed.
When a team is unsplit, the system will merge the "sub teams" together as follows:
The number of volunteers needed for each position across all service times are combined. For example, if there are 2 service times, and 3 greeters are needed for the first service and 4 are needed for the second service, the merged team will need 7 in total.
Volunteer assignments are merged into the single team and the assigned times are the same as they were on the split teams. Declined assignments are removed from the team. If a volunteer accepted one time, and others are pending a decision, all times will be accepted after the merge.
If any split team was set as an assigned team on a plan time, the merge team will remain as an assigned team.
Due to how teams are split and unsplit, it's not guaranteed that splitting a team and then unsplitting later will result in needs and assignments being the same as before the original split.