The EEC document
Hourly entry vs. occupancy count definitions and indicators may help (or at least solve insomnia)
1.2.1. Definition
Occupancy Count named OCC8 for a given sector is defined as the number of flights inside the sector during a selected Occupancy Count time period. This selected Occupancy Count Time period is referred as Occupancy Counting Period.
This Occupancy Counting Period is defined in terms of a Step value and duration value as a picture taken every Step value with an exposure of the Duration value:
• The Step value defines the time difference between the start time of two consecutive Occupancy Counting Periods.
• The Duration value defines the time difference between start and end time of each Occupancy Counting Period.