Dave, After creating and applying the 4dx10h task calender to the pasted contractor activities, the schedule should calculate correctely. The only real “issue” you describe is the inevitable stakeholder confusion regarding the definition of a “day” of duration. The program stores all durations in minutes, and the factor for converting between minutes and days is an attribute of the project file, not the calendar. As a result, your enterprise project will always display the duration of a 40-hour task (4 days in contractor’s schedule) as 5 days, despite the fact that it starts on Monday and finishes on Thursday according to a 4dx10h calendar.
To head off confusion, you might consider using a custom text field to report “Standard Duration,” computed according to a formula like this one: [Duration]/IIf([Task Calendar]=”4dx10h”,600,[Minutes Per Day]) & “days”