protected override bool InternalInRange(RFInterval interval) { var today = new RFDate(interval.IntervalEnd.Date); if (CalendarDay.HasValue && today.OffsetDays(CalendarDay.Value - 1) != today.LastCalendarDayOfTheMonth()) { return(false); } if (WeekDay.HasValue && today.OffsetWeekdays(WeekDay.Value - 1) != today.LastWorkdayOfTheMonth()) { return(false); } return(true); }