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 peoples emails are added
Attention box = specific person
Specific persons 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