> There are a list of elements, and the following code is 
> trying to create a new row to display subtotals.
> There might be any number of Customer rows. Is there a way to 
> check if I've reached the last customer, and then
> insert the subtotal row? The following code is inserting on 
> every row, instead of the last.

Sounds like a classic grouping problem - see
http://www.jenitennison.com/xslt/grouping

Don't think of this as "process all the rows, outputting a subtotal whenever
I reach the last customer in a group". Think of it as "process all the
groups; for each group, output each row in the group and then the subtotal
for the group".

Michael Kay
http://www.saxonica.com/