Hi,
as said this is only to restrict the number of overdue EE that will be processed for one call.
Example you have 1 Million overdue EE in your system this would cause a memory dump when they would be selected in one run. With package size you can say select only 50.000 overdue EE and process them and then start another call.
This is only for exceptional cases. If EE Monitor is scheduled regularly package size should not be needed.
Best regards,
Steffen