Average Monthly Expenses Report/Chart?

[Chris Ingram]

I have been using GnuCash (1.6.4) for about 4 months now to track my
family's (me and my wife) finances, but have been loosly following its
development for much longer.  I am trying to figure out how to best
track historical expense patterns to help us budget and see where we are
overspending.

I'd like to be able to generate an "Average Monthly Expense" report that
shows for a given time period how much we've spent in each expense
account.  I can get close to this by using the Profit and Loss report
and selecting all of our expense accounts in the report options, but
instead of showing me total dollars for each account for the entire time
period selected, I'd rather see the average per month spent.  Also in
the "Expense Piechart" I'd like the dollar amounts shown in the legend
to be average monthly dollars as opposed to total dollars for the entire
time period.

I'd ultimately like to see three of these "Average Monthly Expense"
reports side by side (I think I could do this using the "Multicolumn
View") for three different time periods like last 12 months, last 3
months, and last 1 month.  However, there don't appear to be options to
select the start date for the P&L report as "Start of previous month
minus X" where X is could be 12 or 3 (or any other number of months I
choose).

My question is: How does everyone else generate reports and pie charts
containing such average monthly expenses dollar amounts?  Is this
currently possible?  Also, is it possible to select dates like I
mentioned (Previous month minus 12, etc.)?

If not, should I look into modifying the existing P&L report and Expense
Piechart to have a "show average monthly dollars instead of total
dollars" checkbox?  Where would I start looking to do such a thing?  Is
there any documentation available for creating/modifying reports and
charts?  Should I also look into modifying these to be able to select
the previous month minus X as a start/end date?

I appreciate any help anyone can give me in this area.

--
Chris Ingram
Chris.Ingram@acm.org
http://www.purl.org/net/cingram/