Diagnosis
You have defined time units smaller and larger/equal to DAY as thedefault values.

System Response
All operation time segments are scheduled in the same time unit. Thisunit is specified as the largest of all the time units.
The durations calculated using formulas are converted using the globalunits of measure from Customizing into this largest time unit (24 hourscorresponds, for example, to one day). Because the largest time unit islarger than/equal to DAY, durations that were calculated in a unitsmaller than DAY are scheduled to the day exactly (in other words,taking no account of shifts).

Example
The duration of a time segment is calculated as 24 hours. For anoperating time of 8 hours a day, this duration is scheduled over 3 daysif the largest time unit is smaller than DAY.
However, if the largest time unit is larger than/equal to DAY, the 24hours are converted to 1 day according to Customizing, so that theduration is scheduled over exactly one day.

Procedure
Check whether the scheduling results match your requirements and, wherenecessary, maintain the default units of measure that are smaller thanDAY or larger than/equal to DAY. If required, maintain a new time unit,such as 1 work day = 8 hours.
See also consulting note 150007.