2MB and 6MB for the documents in question - which is, I note, more than 10x bigger than any of our other .SHARED files. I'm guessing that you would suggest this to be the problem, in which case I now need to ask: what influences the size of these files, and what can I do to reduce them?
Those SHARED files store all relevant information regarding collaboration objects, bookmarks, session recovery bookmarks, notes and anything else created by the user. Therefore, if there are a lot of users in a shared / collaboration environment, I'd say there's little more you can do.
Anyway, check the QlikView Power Tools, specifically the Shared File Viewer so you can check what those SHARED files have. This tool can "defrag" these files as well.
By the way, how large are the META files for those QVW? Are you using DMS or NTFS authentication?
Hope that helps.