bitemID on upper form of BP

I am trying to use the CBS picker (bitemID) on a non-cost BP. The documentation states that it's available on any BP upper form except RFB bidder BP, but that doesn't appear to be the case. The BP that I'm attempting to add it to is a single record (non-cost) project/shell BP. Is that an additional restriction that's just not documented correctly?

Where to Use it:

• Upper form of any business process in a project/shell, except an RFB bidder BP.
• Detail form of:
  • Line Items with CBS Code types of cost BPs
  • Line Items with Both CBS Code and Fund Code types of cost BPs