yum client doesn't see new packages though server is updated

I started digging into the webserver logs on the yum server, and didn't find any hits from the IP for the client that couldn't find the files. I didn't understand this at first, since I'd cleared out the cache on the clients. So I did another cache cleanout, this time using

sudo yum -v clean expire-cache

When run with -v, it lists which repos it cleans - and the int-optional-latest wasn't in the list. I figure this was due to the repo being disabled by default. I did another cache-clearing, this time using

sudo yum -v enable-repo=int-optional-latest clean expire-cache

After that, I tried another

sudo yum enable-repo=int-optional-latest install perl-Excel-Writer-XLSX

which worked perfectly.