Yochanan Ben Yohoshuah Zimri, haGaon - Dates don't make sense for Rash's ancestor Yochanan

If he is only 15 generations from Rashi he cannot be 1000 years older.

https://geni.com/2wWvF

1. RASHI רש״י b. February 22, 1040, Troyes, Champagne-Ardenne, France; d. July 13, 1105, Troyes, Champagne-Ardenne, France
2. Rabbi Yitzchak Ben Shlomo Tzarfati, RASHI's father b. 1010, Worms, Rhineland-Palatinate, Germany; d. 1060, Worms, Germany
3. Sharma? ben Elyakim Tzarfati, [RASHI Gd.father] b. circa 1000
4. Elyakim Ben Aharon Tzarfati b. between 935 and 995
5. Aharon Shlomo Tzarfati (ben Ahadam Harofe) b. Worms, Rhineland-Palatinate, Germany
6. HAGAON RABBI AHADHAM TZARFATI
7. Rabbi Yosef ha-Gaon Tzarfati
8. HaGaon Benjamin? Maniumi
9. Yanai ben Yochanan
10. Gaon Yochanan Abayei
11. Abai ben Eliezer
12. Gaon Eliezer ben Yossi Maniumi
13. Yossi Bar Nachman
14. Nachman ben Yochanan haGaon
15. Yochanan Ben Yohoshuah Zimri, haGaon b. 125; d. 170