This is which style of metric the router considers in its SPF computation at this level. It is independent from ciiSysLevelMetricStyle, letting a router in a mixed-metric transition period originate wide metrics while still computing its own paths based on narrow metrics until the whole area's migration is complete. For example, during a phased migration to wide metrics an admin might leave this set to narrow on a given router even after enabling wide-metric origination, so that router's own path selection does not shift until every neighbor has also finished the transition.