This is because the schedule is already set to use the payer as it was originally defined when the schedule was created. To correct this:
  1. Go to the student record and select the Activity tab.
  2. In the upper left corner of the tab, change the View drop-down menu from Activity to Scheduled Activity, and open a scheduled item that you want to change.
  3. On the Apply to tab, change the distribution to match what was defined on the Payers tab of the student record. Any future charges or credits generated for this schedule will use this distribution. Additionally, if you delete and regenerate a charge or credit from this schedule, it will also use the new distribution.
As an alternative, if nothing has been generated from the schedule, you can delete and regenerate the schedule if it was generated from a bill code, or recreate it manually if it was manually entered before.