If I select several items it does not show the change on the printed receipt.

If I select only 1 item on the receipt the change is shown, but if I select several items on the screen the change is shown, but on the printed receipt the change does not appear.
Example: I sell 1 item for $3 and I get paid with $10 and the receipt shows $7 change. But if I sell two items, one for $1 and the other for $2 totaling $3 and I get paid with $10 it does not show the $7 change, it only shows cash $10 amount paid $10.