No. 8 is just one of the signals. There are also no. 9 and no. 10. These signal are used based on the wind speed at HK instead of the storm itself.

For the actual strength of the typhoon, we just call them differently: https://www.hko.gov.hk/en/informtc/class.htm

Although I’d admit the current hurricane is actually stronger than a lot of typhoons: https://www.hko.gov.hk/en/informtc/historical_tc/metinfo_wind.htm