Something I don't understand in the logic of the visitors.
Since quite a while, if I attach 3 work sheets for instance,
it's because they relate together in one way or another.
For a complete story, they should show same number of "download",
but it is not so, so far. May be the download counter not
counting correct ? Just a personal observation.

I think there might be different reasons

One possibility is that someone downloads one of the attachments just to take a look to the argument then leaves the others untouched if it doesn't find it interesting enough.

Another might be the opposite, multiple downloads because it founds one worksheet interesting, and he needs to look it again in another machine.

A third reason is browser's download vs open (the second downloads a temporary file, hence if you close the worksheet and the browser and you want to open it again you have to download again the file)