[O] org-collector calculated rows?

[Rehan Iftikhar]

Hi Org list!

For those of you familiar with org-collector (ie. propview dynamic
block) is there already a way to include a calculated row?

For example, in the demonstration of how to use org-collector @
http://orgmode.org/worg/org-contrib/org-collector.html, I'd be
interested in:
  * Simple Example: displaying the sum of the "Amount" column
  * More Complex Example: displaying the mean of the "Amount" column
for each week.

Does anything like this already exist?

-- 
-Rehan