Calculating Average in SubTotals

I have a report that subtotals by games. For example, one game is played 16528 times and the amount of money played is $19443.75. The correct subTotal average for the game is $1.18, but SQL Reports returns $1.09. I tried various ways of calculating the subTotal average, but with the same results. Is this an issue with SQL Reporting, or does anyone know of a method for calculating a subTotal average? Thank you.

The Average aggregate in Reporting Services works very similar to the Avg aggregate in SQL. Only values that are different than NULL contribute to the average, e.g.: the average for the following set { 2, 3, 2, NULL, 3 } is 10/4 = 2.5, instead of 10/5 = 2.0.

Note: you could convert NULL into 0 either in the query or based on a RDL expression if you want the behavior that NULLs are treated as zero.

-- Robert