InfoPath Dev

We're using a InfoPath 2003 form to collect some data from various users.  A calculated field is generated by five fields of information.

The calculated field works correctly the first time you type the data in, but if you go back and try to change a number in one of the five fields, the calculation does not update.  The only thing that is different about this field is that it is used in the formula twice.

 Is there a way to make it so the user can change this field and have the calculation update without reloading the form?

 Thanks!

I don't recall whether this option is available in IP 2003, but in IP 2007, in the properties for the field, we can select to update automatically if the fields that are used in the formula are modified. I suppose if the issue is with a single field, you could add a rule to that field to update the calculated field....