Jon - I have a final question.  The suggestion you gave me earlier works
great, but since my workbook is so bloated, the chart update time is a bit on
the sluggish side (for reference, I am using the method you detailed on your
website, using a "helper" column that updates according to the offset value).
Can I use OFFSET directly in the SERIES formula?  If so, what is the syntax,
because I get an error every time I try to modify it.  

Wazooli