This is not reflected in MS Project automatically, and I wonder if I'm missing a setting somewhere or some action to be done. because the MS Project team doesn't have to dog-food their own product.
Really MS Project isn't going to recalculate the rest of the project every time you change the completion of a value (and it may not be appropriate either).
However, all the fields seem to be linked to each other.I'm basically forced to change the planned duration to be the actual duration, making the idea of separate actual and planned durations meaningless.It can also screw things up nicely (ask anyone who has accidentally "rebalanced" their project - everything goes fubar) You can sort of do what you want by re-leveling the resources: Go to Tools - If you have set start dates to your tasks that's how they remain.You have to make each task a predecessor to the other for them to shorten up if one finishes sooner then planned.What you will see (based on your description) is that the resource is less utilized then previously reported over that work period.
So, if you had the person 100% utilized, they are 1/12 less utilized now, allow you to add additional tasks to him.
Instead, all you need to ask them is “Are you on track to complete this task”.
If yes, proceed with the steps below, if not, you will need to re-schedule this task.
I've tried the obvious step of selecting a task and pressing the update button.
The Update Tasks window pops up with what I take to be the planned duration/start/finish in the top and actuals in the bottom.
Look for a book called Dynamic Scheduling with Microsoft Office Project 2007 to learn more.