Remove comment styling prompt from custom post type

I didn’t want to the comment styling prompt on my site so used the following:

function remove_comment_styling_prompt($defaults) {
		$defaults['comment_notes_after'] = '';
		return $defaults;
	}
	add_filter('comment_form_defaults', 'remove_comment_styling_prompt');

This worked fine for normal posts but not for my custom post type which has its own seperate comments template. Is there some change to this code that I need to make to do this?