Okay, I think I may have run up against the design limitations of the pivot grid widget...

Here is what I'm trying to do: I need to make a cube with a dimension that averages based on leaf-node values in the cube, rather than on it's own value.  This statement probably  doesn't make a whole lot of sense out of context so here is the specific example:

Let's say we have a cube with three dimensions: Average Unit Sales Price (AUSP), Quantity, and Revenue.  AUSP is equal to Revenue / Quanity, which the cube supports, so so far we don't have a problem:

AUSP     Quantity     Revenue
 1000                 2             2000
     20              100            2000

The problem comes in when it comes to aggregation of these dimensions when they are collapsed.  Both Quantity and Revenue should aggregated using straight summation, so that is easy... But AUSP needs to remain dynamically calculated based on (Sum of Revenue) / (Sum of Quanity).  So correct aggregation would look like this:

AUSP     Quantity     Revenue
 1000                 2             2000
     20              100            2000
----------------------------------------
  39.2              102            4000

The only built-in AggregatorType that looks like it might be able to do this is "Calculated", but there is no documentation anywhere as to how to use it, specify a formula, etc...

Does anyone know how this works?