Should extensions define individuals of the class saref:FeatureOfInterest ?

Class s4watr:Water is a subclass of saref:FeatureOfInterest, and has different individuals. It may be problematic that this class contains generic individuals such as s4watr:DrinkingWater etc. which will be the object of measurements of all kinds. It may be better to have a pattern where these concepts are instances of s4watr:WaterKind, and an instance of s4watr:Water (a specific quantity of water) is linked to its kind.