Can anyone explain the "request" and "document" tab integration/communication within a client's profile on Intuit Link?

[CC2040]

I use ProSeries Professional and, in the past, it appeared that the "document" tab within a client profile simply weeded out typed responses and gathered all of the documents in one place.  I have just recently noticed that some documents appear in both tabs, others appear only under the "request" tab and others appear only under the "document" tab.  The location where the document uploads does not appear to be attributable to whether a request was made or if the client is providing something independently, nor does it seem to have anything to do with the file type, any of my settings and/or browser being used.  I’ve also tried researching Inuit’s intention for the separate tabs to be used since they share a lot of information, but can’t find anything and spent three hours on the phone with support unable to assist.  Does anyone else have insight on this?