PANS OPS allows for increases in MOC of up to 100% in "mountainous areas".
"Mountainous area" is defined as an area of changing terrain profile where the changes of terrain elevation exceed 900m (3000ft) within a distance of 18.5km (10NM).
So, terrain over 3000ft does not automatically qualify as a "mountainous area" and an increase in MOC. However, some countries may well choose their own definition, or simply define the areas.
PANS OPS is an ICAO manual, and does not have the same status as Standards & Recommended Practices. It can't really 'contravene' any locally developed documentation.