Reports by Category totaling with transaction amount not category amount?

I am running a Spending report by category. The transactions listing use the total of the transaction as the spending amount not the amount assigned to the category.

Example:

Transaction to XYZ company for $1000. The amount is assigned to two categories, A and B, $500 each. The spending report for category A shows $1000 and the spending report for category B shows $1000 for the transaction. I am trying to get an amount of spending by category.

What am I doing wrong?