Multi is the number that the average value is above the rules value, multiplied. ie a Multi of 10 means that average CPM value is 10x the rules value. Gives you an idea of how overpriced some things are incomparison to the rules values.
# is the number sold, but might just be listings that had that in it, or the total sold including multiples in the same listing. Or something like that.
For the future, CPM questions should always be directed at my inbox (I answer all of them and after all, it's not official part of SWC and I'm the only one coding it).
Or check your spam folder. I have added your account after the first DM already, if you haven't received your password yet, it's due to your email account flagging it as spam or deleting it.