I'll take a look at your file now.

No, I regularly use EP4 to export single sub-categories, modify and upload corrections/changes. Yes, you can just use 1 line of data. If fact, that is the very best first thing to do when you want to ensure your data is importing correctly.

Also, be sure you are doing a backup of your data first before running an import. There is an update MySQL database backup tool that work fine on most databases.

BRB