When I look at these two examples from the English to the Spanish there is no clear indication of why the pluscuamperfecto de subjuntivo is being used vs. the condicional.
Si no hubiésemos comprado esta casa, hubiésemos tenido más dinero para vacaciones.
If we hadn't bought this house, we would have had more money for holidays.
Si no hubiéramos comprado esta casa habríamos tenido más dinero para vacaciones.
If we hadn't bought this house we would have had more money for holidays.
