To edit the items -

1. Archive any existing invoice batches.
2. Select Edit - Items from the main IN toolbar.
3. Select the item and in the Ordered, Shipped & Backordered fields, and enter a whole number instead of one that has 2 decimal places. (If you do not display one of these fields in your invoice entry screen, then while you are in the Edit Item area, you will have to visit the Item's Options and check those boxes to be able to change their defaults first, then go back and toggle them off again.)

Regards,