This is because the broader-based political power incorporated a class of Gozoku into their administration in order to stabilize the political power, or adversely Chihokan became Gozoku when the ruling power of the broader-based political administration weakened.
広域政権側が政権安定のために豪族層の政権内への取り込みを行ったり、逆に広域政権の支配力が弱まると地方官が豪族化することがあるからである。