Help to dynamically update Excel chart

Hi,

I have a small spreadsheet; 6 columns. I created a chart to show data from these columns. As new rows are added, the chart needs to update automatically. I found some info on the web and used Name Manager create a formula for each set of data. Then for the each series on the chart, I revised the SERIES to point to the named range. This all works perfectly fine until I get to row E, for some reason, that dataset (which is just the date and the Cust column), I cannot modify the SERIES. I type it in, hit enter and nothing. I can trick it by choosing another column, then drag it over to the right column using the mouse. This works ok, but gives an error and I worry as more data is added to the chart, it may cause problems.

I have attached the file...