Loss of formatting is a known problem with pivot charts. There's
information in the following MSKB article, suggests recording a macro as
you apply the formatting:

XL2000: Changing a PivotChart Removes Series Formatting
http://support.microsoft.com/?id=215904


s de maia wrote:
I have created a pivot chart as an objecct in another worksheet. The data
labels are on the chart in a font larger than I want (Arial 19). I can click
on each of the series, and reduce the font to Arial 10, but as soon as I
refresh the chart, the font goes back up to Arial 19. The default font for
my excel spreadsheet is Arial 10.


--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html