I was getting around the lack of dynamic calculations in <=1.5 by doing the work in Analysis for Office, creating a Web App, then copying the datasource into the Design Studio App I was building.
I could never get smart copy to work...no matter what I tried...
In the app I am building, I am displaying a line chart of the running sum OR comparative column chart of week or periods or quarters, this year vs. last year.
I saw similar issue in 1.5 with datasources from AAO with dynamic calcs. but figured it was something I was doing wrong...and knew it was coming to DS 1.6
james