What is the criteria when grouping requisition lines into autocreated PO

Per the purchasing user guide, got following information. "Select the Grouping for requisition lines on the document:
Default: Combine requisition lines for the same item, revision, line type, unit of measure, supplier item number, and transaction reason onto one purchase order line.
Combine requisition lines for the same item, revision, supplier item number, and line type onto one RFQ line."

In bug 3201308: AUTOCREATE DEFAULT GROUPING HAS CHANGED-NEED 11.5.8
AutoCreate default grouping option was altered in 11.5.9 in a way which does not suit client's business. In 11.5.8, it grouped requisition lines
with the same item, revision, line type, unit of  measure, supplier item number and transaction reason and created 1 PO line.