If hard palate is not a component of oropharynx then how does nasopharynx extends up to hard palate ? Is it not soft palate?

if hard palate is not a component of oropharynx then how does nasopharynx extends up to hard palate ?? Is it not soft palate?

Nasopharynx is the uppermost part of the pharynx. It lies behind the nasal cavities and extends from the base of skull to the soft palate or the level of the horizontal plane passing through the hard palate. Thank you.

Ref: P L Dhingra, Shruti Dhingra - Diseases of Ear, Nose and Throat Head and Neck

Soft palate(uvula) is a mobile structure… So we can’t it as exact landmark… Isn’t it the reason… !

reasonable but let’s see what is correct