I have created hundreds of dynamic charts using information from Jon Peltier
and Tushar Mehta with great success, but now I have one that is stumping me.
Using Excel 2003, I need to chart monthly data of the current year using a
column chart that updates as data is added each month (which I know how to
do). The part I'm struggling with is adding a year-to-date total (that also
needs to automatically update each month) as the right-most column of the
chart. This is the standard format my company uses for charts with YTD info
so I need to stick with it.  

I've done this before on charts where the data is a rolling 12 months, but
not where the number of columns of data will increase each month up to 12. I
have a dozen or more charts I need to do this with so any help is greatly
appreciated.