Report Grand Total Miscalculating Overtime

I have a report based on a query that uses the following calculation in a
text box to calculate the total amount paid (including overtime) to an
employee:

=([On Std Hours]+[Off Std Hours] + IIF([On Std Hours]+[Off Std Hours]40, .5*
([On Std Hours]+[Off Std Hours]-40), 0)) * [Employee Data_Rate]

This formula works perfectly to total individual weekly totals. However,
whenever I use the same calculation in the report footer to calculate the
grand total which sums up every employee for the week, the grand total is a
lot higher than it should be. For example, I hand computed the total amount
paid for a week and got 30,667.74 and the report is showing 50,951.88. I'm at
a total loss of what could be causing this. Any help would be greatly
appreciated!

--
Message posted via AccessMonster.com
http://www.accessmonster.com/Uwe/For...ports/201004/1