How to Compare Weekly Lookahead Schedules and Report Variances!!

When I create a copy of my current schedule in P6 and save it as target schedule, next week, when I update the schedule and compare their finish dates with last week, the activities that have started, show different finish dates and different variances than what I should expect. My column titles are Start, Finish, BL1 Start, BL1 Finish, Variance BL1 Finish. Any suggestions??

The only solution to this problem is custom data items and global change. Unfortunately the issue remains with P6 . The Solution: 1 - Create custom data fields for last weeks dates 2 - Move last weeks dates in those fields using global change 3 - Update the schedule 4 - calculate the variance using a global change There is also another solution for this if you know .asp or .cfm or .net web applications. You can create a web page that looks at each database and easily calculates this, so you dont even have to worry about anything AT ALL