One Delivery Type, Many Invoice Types

We have a peculiar invoicing configuration where we just use one sales order type (PCRE) and one delivery type (ECRE) and many invoice types, one for each plant, my problem its that for the last plant we must be missing a configuration since when creating a new invoice (VF01) SAP by default suggest an outdated invoice type (I am erasing it from VTFL next) but since this is also entered with the rest of the plants where we do not have problem I am wondering where can I find link between Invoice Type and delivery when the delivery type its the same for all the plants?

in other words: how does SAP knows the correct invoice type since the delivery type and sales type are the same for every plant, since only our invoices are different for each plant?

I have been looking here unsuccessfully: VTLA , VTFL, VTFA, V/54, OVL3 and others.

Thank you and Best Regards,

Carlos