Most of the New Holland Wagons are designed to set "Tie Bales" in place on the go. This is necessary to hold stacks together. Fifth layer  in stack is the tie layer and the top caped with a tie layer two wide 

On larger wagon two or three tie layer are recommended.

Bottom picture has two rows have been slid to the back of table, then three bales are loaded and , the tie lever set to create the automatic tie operation. the center bale is kicked off  and it loads two at a time to finish the operation.  See Tie operation later.