Ability to extend download length for all files at the same time.

[bluesrockuniversity1470]

Sometimes I have customers who have bought a lot of download products, and due to the fact that the files are very large, they run out of time. In these cases I would like to extend the download time for all files at once, rather than having to enter the extension for each file.

I would also like some way to say that the download expiration date is related to the number of products paid for.