You could convert those unused VPP App codes to managed distribution apps. Have a chat with your Apple rep.

@mvu: There aren't that many apps so I would just prefer to download codes and upload apps asap as opposed to waiting to hear from my apple rep. I was able to upload codes a few months ago, but now I cannot and I can't remember if I used a certain template or if it was just a the codes in an .xls doc.

I found that I had to add the app and then upload the codes under the VPP tab.
I was using the old XLS file format.