I know for a fact that dual screens have worked correctly long after 0.162

The issue here is that it seems you're using unofficial builds and/or unofficial compiled builds because of this spotted in your mame.ini

Code
# Opciones del Parche Nonag
#
Desactivar_parche_nonag 0
Desactivar_parche_pantallas_de_carga 0


Which means that you'll get different results or different bugs that don't exist when compared with someone using the official build from mamedev.org

Now I'm not totally ruling out that something isn't wrong at this point, but more investigative work might be needed.