Question related to CIF of PDS to SCM

Hello Experts:

In transaction CFM1, you can send the PDS to SCM either by selecting the PDS(ERP) or BOM. I was wondering if you can shed some light on the differences if any. My only objective is to send a PP/DS PDS to SCM. I also attached a screen shot of both of these options. I am using a SCM 7.0 EHP3.

Thanks,

Satish Vadlamani