Attachment category 'internal to requisition' not showing for Process Requisitions?

Summary:

All attachment categories except for (internal to requisition) will show the paper clip attachment on the line level on the Process Requisitions Page. When clicking on the requisition number, then once in the requisition it will show all attachments for all lines. Is the category type 'internal to requisition' the only one by design that won't show the attachment on the line for Process Requisitions? We would like to understand this functionality more.