ERS Vendors

Hi,

I'm currently looking at ERS Vendors in SAP (i.e. those when the GR is received automatically pay the Vendor without receiving the invoice) and had a few clarification questions I was hoping people could help with:

Does the original PO require to go through the standard PO approval/release process?

After the GR is entered in SAP, is there an additional approval step prior to the vendor being paid?

Is there a table or flag I can use to extract GRs that have been automatically paid without an invoice being sent?

Any help would be great thanks!