So it turns out that the five-week display is okay, and the real culprit is that the extracts on the server are not being refreshed on the schedule set in the tasks.
I will ask in a separate forum question the difference between published data connection and published workbook refreshes, because I think that's the main issue for us.
If you connect to a published data source on Server, and leave it as a live connection, you can update the published data source and your workbook will reflect that. However, anytime you use a local extract in your workbook (including if you connect to a published data source and create a local copy of the extract), you must refresh at the workbook level in order to see new data.
I hope to see more functionality for the Data Server in the future, so that we can connect one published extract to many files and retain good performance.
Thanks for the information. So what it the "right" way to do this? That is, I want to develop my workbook, publish it, and have the server update the extracts automatically so I don't have to refresh at the workbook level, AND my customers get the benefit of the extract speed.
Just publish packaged workbooks with extracts embedded, and set a refresh schedule on the workbook.