Sometimes when I add a new line (not always), the simple formula will show the zero value ($0.00). Most of the cells work fine and the value shows as blank. What would cause this to happen?

I have gone to Excel Preferences and unselected the box 'show zero values'.

When I go into format cell and look there, the number tab and selecting 'currency', the sample field at the top shows $0.00. If I look at the format cell with the fields that are correctly showing a blank cell, the sample field at the top shows a blank field. How can I get that field to change for these few cells? Any help will be appreciated.

NINDY