Section 21. Certain sections not to apply to bills recommended by certain commissioners or public agencies

Sections 15, 16, and 17 of this article shall not apply to any bill, or the amendments to any bill, which shall be recommended to the legislature by commissioners or any public agency appointed or directed pursuant to law to prepare revisions, consolidations or compilations of statutes. But a bill amending an existing law shall not be excepted from the provisions of sections 15, 16 and 17 of this article unless such amending bill shall itself be recommended to the legislature by such commissioners or public agency.