Inconsistent roll up behavior in a PerformancePoint grid object

Question

I have a basic dashboard which consists of a single "grid" object displaying 3 measures across time broken up by a business unit hierarchy...

When filtering on a single item in any of the levels in the business unit hierarchy, everything rolls up correctly...

However, when I filter on more than one item in the same level, the rolled up values are no longer based on visual totals...

In the image above, the values in the "All" row represent values for the entire unfiltered business unit hierarchy. It would be ideal if the grid rolled up as if "VisualTotals" was enabled...regardless of the filter selection. In that case, for the second image above, I would expect the values in the "All" row to look like...

PO E-PO Count = 3531     (497 + 3034)
PO Count =      7923     (2094 + 5829)

I've considered using the VisualTotals() MDX function, but I'd prefer not to customize the query because I read somewhere that it reduces the end users' ability to dill up/down/across.