Thanks again Jerome, I updated to the latest version and now the "download number limit" field is there in the product file edit window as you said.
However, I set the limit to "1" in the file edit window (so now it's set to 1 in both places: config. default and individual file) and I can still download as many times as I want. (I downloaded the file 5 times, and in the product window, under Files>Downloads it shows 5/1.)
After the first download, should I be getting a message saying I've reached my limit? Please advise! Thank you!
PS. Although the add/edit file windows are all the same, is there a difference in the way limiting downloads works, depending on whether the file must be paid for or is free of charge?