Only part of my purchased music appears under Purchased
I have hundreds of songs purchased via the iTunes store over the past several years, yet only 38 of them appear under the Store Purchased items list. This occurred prior to and after my upgrade to iTune 10.3 (no difference). I haven't checked every single song, but it seems that the songs that appear under Purchased show my current .me email address, while the songs that do not indicate my older Cox or .mac email address (when I Get Info on the songs), although I can't figure why that should make any difference whatsoever (since all of the addresses are linked via my MobileMe and iTunes accounts).
How can I get all of my Purchased items to show up as being Purchased (both within iTunes and on my iPhone)? What might cause this problem?
Mac mini, Mac OS X (10.6.7), MacMini 2.6 GHz; iTunes 10.3