Subsections (2) and (3) apply where—
(a) a fundamental provision is not incorporated as a term of an occupation contract because of an agreement under section 20(1), or
(b) a fundamental provision is incorporated with modifications because of an agreement under section 20(2).
If as a result it is necessary that another fundamental provision or a supplementary provision (see Chapter 4) is not incorporated, that other provision is not incorporated.
If as a result it is necessary that another fundamental provision or a supplementary provision is incorporated with modifications, that provision is incorporated with the necessary modifications (in addition to any modifications made because of an agreement under section 20(2) or section 24(2)).
But subsections (2) and (3) do not apply if their application would have the effect that a fundamental provision mentioned in section 20(3) would not be incorporated or would be incorporated with modifications; accordingly, the agreement mentioned in subsection (1)(a) or (b) has no effect.