Hi,
I am not sure if this is possible to be honest. It is not the plugins fault, but the SQL server does the ordering alphabetically, since the titles are strings and not numbers alone.
If you check the ordering:
Artículo 1003..
Artículo 1013..
Artículo 1023.
Artículo 103…
..alphabetical ordering is correct. It would only work differently, if there was a leading-zero character before the strings:
Artículo 00001..
Artículo 00002..
Artículo 00003..
Artículo 00004…
..and so on.
I could try to make a modification to cast the titles as numbers, but it may not work either as there are alphanumeric characters as well. If you want, you can add temporary FTP and back-end details, and I can try a modification, but I don’t know if this is possible to achieve.