Clarification is fine, but "MyClass and MySubclass are instances of Meta:" is 100% true. Declaring a class to have a metaclass (or inheriting from a class with a metaclass) means that the class itself is an instance of the metaclass.

New instances of the classes with metaclass Meta are not "created using Meta"; Meta modifies the creation of the classes themselves, not instances of the classes.

Point is, your suggested change is half wrong (new instances of MyClass and MySubclass aren't directly created using Meta), and half misunderstanding the current documentation ("MyClass is an instance of Meta" already means "MyClass has the metaclass Meta").