misplaced curly brackets for db_prefix_tables ?

Hello,
First, thanks for your module. It is very valuable and I hope to adapt it successfully to my particuliar project.
If I may, I encounter a little bug when the database uses prefixes. Following the doc, it seems the curly brackets should enclose only the table name.
Here is a quick patch if it can help.

For the moment, I'm working on a hook_user() to your module so the user knows how much quota he has left. It should be a single function of about 20-30 lines. Would you be interested ?