Why should it? Expression 'balance = calcbal()' means that VFP have to compare value of balance with result of calcbal(). Try

_VFP.SetVar("balance", calcbal())

Keep in mind that UDF() in report could be called miltiple times even for one detail record.

>I have created a report variable, balance, and want use that variable for a field on the report. I have a UDF to return the value of the current balance. When I put the expression balance = calcbal() into the on entry expression for the detail band, the variable is not getting updated. I can use just calcbal() as the expression for a field and get the correct balance, but I would rather have it defined as a variable in the detail band so I could do some other calculations with it. Am I using an expression here in the wrong way?
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>Thanks in Advance