What is purpose of BA partner in vendor master

Hi

We have some problems with output determination in purchase order. We have set up output in MN04/MN05 for parter type LF and the output is created with parterner type LF but with the partner number from partner type BA.

After a lot of Investigation I found that this is SAP standard behavior http://saphelp.ucc.ovgu.de/NW750/EN/c0/80b65334e6b54ce10000000a174cb4/content.htm

So if BA partner exist it will be used in the output instead of LF partner.

Also I found - via OSS note 2741050 - some customizing that says that partner types LF and BA are mandatory for all vendor master records.

Unfortunately I can find no one in our company that knows why BA partner is mandatory. also I can find no explenation what the BA partner is used for (except this partner substitution in PO output determination).

So my question is - what is BA partner used for and what will happen if we make it not mandatory and remove in from our vendors?

System: SAP ERP 6.0

Best regards

Thomas Madsen Nielsen