Susan /Tom,
Thank you so much for explaining this to me.I have realised since my
macro is in Worksheet_Calculate event its running each time I do any
thing on Worksheet and ultimately hiding the Undo button.
As you can realise that although I obtain the desied metric correct by
writing the macro its creating another trouble where users can not
undo their actions.For exaample if they bring down the Page field in
the row they can not undo it and to get the normal Pivot they have to
close it and then open it again.

Do you have some solution where I can get the correct metric and at
the sam time have the mormal Excel features working.

Regards,
Shailesh