Bill C-20 amends the Constitution Act of 1867. It amends the rules for adjusting the number of members in the House of Commons. This amendment proposes to amend those rules so as to keep the numbers of members at the current level.
The House of Commons Procedure and Practice, second edition, states on page 766:
An amendment to a bill that was referred to a committee after second reading is out of order if it is beyond the scope and principle of the bill.
In the opinion of the chair, maintaining the current numbers of members of the House of Commons is contrary to the principle of Bill C-20, so it is therefore inadmissible.