It's correct that the provision only amends section 17 of the act. There's a difference between sections 16 and 17 in what they do. Section 16 deals with original orders. It is based on the best interests of the child. So the court, looking at whether an original order should be made, would look at all the circumstances of the child, and one of the circumstances the court would be required to consider would be whether there was a terminal illness, or whether the individual was in critical condition.
Under section 17, one difference is that this two-step analysis is required, so you have to prove a material change in circumstances. That is one distinction between the two sections.