Project duration not reflecting overall original duration

Member for

20 years 6 months

Its a function of how P6 calculates durations for summary bands. If all tasks within a summary band use one calendar, then the summary band will also show duration using that calendar.

If there are a mix of calendars, then the summary band will use the project default calendar. So you may want to swtich 5the project default calendar to the 7 day week calendar you are using for the summary activity.