Plan dates change when project opened in 2003 vs 200

A

aq

Project created in 2003. A group of tasks is using an alternate calendar (7 8
hour days per week) and has lag times. The lag time calculation appears to be
using the alternate calendar as well. When this project is opened in 2000
(which has the same calendat) the same group of tasks now has different start
dates which correlate perfectly with the lag time being calculated using the
standard calendar.
Is this possible? Can it be fixed so that dates appear the same in both
versions of project.
 
Top