Hey, thanks.
I've done a lot of research since posting and have learned a few things. Quick resolution for anyone looking at this post for answers, however: use the File Manager in CPanel to change permissions down.
My results:
First, I went into CPanel and used the File Manager (which I find slower and more tedious to use, but am happy it's there) and had no problem changing down to 444.
Then through Filezilla, changed it back temporarily to 644, just to see if it could be changed down to 444 post-File Manager change. Nope. Couldn't be done.
Tested permission changes with another file, not in Zen Cart, with same results, just to confirm it wasn't a cart software issue.
Evidently, Filezilla doesn't permit changes to 444 through our ftp login. Wondering now about "owner" definition. Your advice to check that out is excellent. Thanks.
Also found information about encountering this problem in Zen Cart FAQs.
Hope this helps somebody. It was a lot of time spent trying to figure out why ftp was misbehaving, but inquiring minds want to know.
