Hi, I just tried it out to remember how this works.
If you select in Merlin Project just one item, for example row #0, the script will transfer in OmniFocus a new folder with the Merlin Project import title and an item of row #0.
If you click in omnifocus the item listed under this item, you'll see the complete structure as defined in your Merlin Project document.
See screenshot here
If you select several rows in the Merlin Project document, the script will transfer the rows as single items.
See new screenshot
So now you know what to select before calling the script in order to transfer the items the best way you need them.
Best regards