There have been times when activities in Primavera don’t Start or End on correct dates despite the math saying otherwise . There are several reasons that can cause this to happen, lets look at them in this post.
1) Out of Sequence Activities – These are activities that have started before the predecessor activities are completed. These activities are created when you using “Retained Logic” as your scheduling preference. This creates non-working periods and this can cause the activity to be pushed out of the normal calculated dates. You can check which activities are being pushed Out of Sequence by checking the “Schedule Log”. You can choose “Progress Override” to schedule and correct these dates or change relationships for these activities. For a better explanation on these option check this blog post Scheduling Options – Progressing Activities .
2) The activity calendar contains non-work time that is pushing the finish date out.
3) Resource Leveling – “Level resources during scheduling” option should be unchecked in “Schedule Options” when you schedule the project.
4) Multiple calendars – If you are using multiple calendars and the number of working hours do not match the Time Period settings under Admin Preferences then the activities might end on a different time of the day.
5) Constraints – If an Activity has an “As late as possible” constraint. The As late as possible constraint allows an activity to start or finish as late as possible without delaying its successors. This constraint sets the early dates as late as possible without affecting successor activities. Even if the activity is started, the Finish date can be pushed later in time if positive total float exists when the As late as possible constraint is applied. This will make the Finish date appear to be later than it would be based on the remaining duration.
6) Project has Activities with Actual Dates > Data Date – To check if any of your activities has this problem you need to go to Tools, Schedule open schedule log. In the schedule log, you need to check and see if any activities are listed in the Activities with Actual Dates > Data Date section. If yes, then you can either remove the actual dates, or move the data date after the actual dates.