Calendar Entries

I have set up a Work Centre called Packing with a Shop Calendar called PACK. The shop calendar has two work shifts. the DAY shift runs from 08:00 to 16:00 and the EVEN Shift runs from 16:00 to 2:00 am (next day). The DAY Shift has 3 operators, the evening shift has 2 operators. When I run the Calculate Work Centre Calendar Report with filters Work Centre = PACK and Work Shift Filter = DAY the program generates Calendar Entries for both work shifts DAY and EVEN. I only want to see entries for the DAY shift. I am using Nav v4.0 SP3. Anyone able to replicate this or is this the way it works?