Summary tasks not summarizing task durations all of a sudden

[Trev]

Here is a scenario

TASK DURATION

SUMMARY A
SUMMARY B 5h
TASK A 1h
TASK B 1h
TASK C 5h

Here is what I did

The SUMMARY B task was calculating 7 hours perfectly. In order to
update multiple tasks all with 1 hour duration did a CTRL + A and went
into task information and changed duration to 1. Now my intention
here was to save time and thought I would do it and see what happens.
Sounds logical. However an autosave saved it after I did this and now
im stuck. After the update the SUMMARY B lines do not calculate
correctly. It appears to take the highest amount. In the example
above I can change TASK A to 2, TASK B to 4 and SUMMARY B will still
show 5. If I change TASK A to 10, SUMMARY B will show 10. Just to
make it more complex the SUMMARY A level items are calculating the
SUMMARY B levels correctly. So it appears to be limited to the third
layer.

I am obviously a MS Project Newbie and need advice on what to try. I
tried to do a run macro thing but it kept telling me to roll them up.
I could not find proper instructions on how to roll up. Im soon going
to print this project off and roll that up... and smoke it.

 

[Sean]

Trev:

Duration at the summary level isn't a simple sum.
Instead, duration is a measurement of the span of time in
between the start and finish of tasks. So if all tasks
under summary B have the same start date, the longest
duration will appear in the summary duration field - in
your case it's 5 hours. When you apply dependencies to
the tasks you will begin to see duration wiggle around.
So if you make A, B and C finish-to-start dependent, then
you will see Summary B duration go to 7 hours, or the
span of time from start to finish.

Hope this helps!