Horizon in the APS settings refers here to the calendar selection, defined by the user, which will be targeted by the APS (e.g. 23 August 2017 to 21 November 2017)
Keep in mind that the solution will always process dates according to 4 criteria :
• The “birth” date or date the task was created
• The scheduled start date of the task
• The expected completion date of the task
• The target date of the task, or deadline
These 4 data remain important selection criteria and action items in the scheduling of tasks and processing of results reported by the APS.