when you hit the plus on an order to add another item it carries over the call number in the new item but nothing else, it should carry over the entire item record since most likely all the ordered items will be the same at this stage of the game
My test shows that any data entered in a text field is copied, but any selections made in <select> lists are not.
Thanks for testing further, the only typed field I had filled in was the call number :)
I just retested this with various pull down and free text item fields - they all copied after adding the first item on the order. Marking fixed, please reopen if you still see problems.