It is just the same as it used to be when Maddie, Jono, neil, tilly, callum, ash, rob, scott, barney, annalise were all added when the cast got really big and they had to extend a little
Never understood why the whole cast has to be in the opening credits. There's too many of them so it drags on. Neighbours also have the cast at the start but there are less characters and most of them are in threes.