Inconsistent actual material costs

[Astroboy]

Here's one that's got me scratching my head big-time.

We are using material resources to capture budgeted and actual costs.
We have a "Labor" resource (because time does not necessarily equal
money here) and an "Equipment" resource in our Enterprise Resource
Pool. Both have a cost of $1/unit.

During the planning process, the PM assigns these resources to a
summary task and gives each the appropirate number of units (dollars).
He/she then saves a baseline and publishes the project.

During the execution of the project, the "Labor" and "Equipment" costs
are updated using information from a report from our Finance Dept. The
PM goes into the summary task and changes the units for the "Labor" and
"Equipment" resources to match the report.

In most cases, both the Actual Cost and Cost fields update to equal the
sum of Material units plus Equipment units. This is what we want to and
expect to see.

In some cases, however, Cost updates correctly, but Actual Cost updates
to a percentage of Cost that equals the % Complete of the summary task.


I can't figure out what's going on here. Any thought?

 

[Gary L. Chefetz [MVP]]

Astroboy:

Assigning resources to summary tasks is a bad practice. Any work values that
get created in the subtasks will be inherited by the summary value and cause
pollution in your data. Apply the resource to a real task, the cost will
rollup to the summary.

 

[Astroboy]

Thanks, Gary. I'm constantly encouraging our PMs to assign their work
resources at the lowest level of the WBS, and had a mild suspicion that
material resources were working the same way.

Thank you for your help!