​1. In working schedule, it's possible to have 0 hour schedule.

2. Create time off, and choose employee which has working schedule 0 hour. In this example, Administrator takes holiday from 21st February until 5th March. The duration is 8 days. It counts the days which have 0 hour working schedule but doesn't count the pulic holiday.

It should also work with working schedule which has 2 weeks calendar.