When you are preparing an order, the attention box controls not only the name on the order but also the recipient when you send it.
In short:
Attention box: contact name
Contact email used
Attention box: empty
Contact email and all individual people's emails added
Attention box: specific person
Specific person's email used
See below for a for an example with a test contact and the three possible scenarios at the PO stage.
Contact
Attention box = Contact name
Attention box = Empty
Attention box = specific person