Calculated Field

Hi Community,

I've one calcuated field on order form, which is depending on two preceding fields. Here my query is that if "Sales order Total amount" field which is currency type not contain any data and "Line Detail amount" currency field contains data then calculated field "Grand Total" does not shows the total,

If i will enter 0 in "Sales order Total amount" filed and save the record it will show the total in "Grand Total" field which is calcualted field.

Can please anyone suggest the way to how to resolve this?

Thanks,

Harry