Using Update Progress function in P6 updates the activities using the Planned Dates not the current schedule dates.
The Planned Dates are very complex and their calculation method is outlined in my P6 book, in summary:
1. When an activity is Complete or In-progress they match the status of the schedule before the last update.
2. When an activity has Not Started they match the Early Start and Early Finish.
The problems with the Planned Dates:
1. The Planned Dates are dates that most schedulers would not want displayed.
2. These dates displayed as the Project Baseline bars and Primary User Baseline bars when no baseline has been assigned.
3. Theses dates are used by the Update Progress function and Apply Actuals function.
I strongly recomend that you never ever use the Update Progress function in P6 as it will often change Actual Dates.
Some people use a Global Change to set the planned Dates to the Start & Finish dates, but if you do this you may alter the Original Duration and change the % Complete calculation.
This is one of the many functions that Primavera have written into this product that make it very hard to use.
Paul E Harris
Eastwood Harris Pty Ltd, Melbourne, Australia
Planning and Scheduling Training Manual & Book Publishers, Consulting and Training
www.eh.com.au