I would say you got it right.
Skarbrand is say battleround 2 no wounds, he charges in incandescent but slaughter is on 4 and total carnage on 5+
You do not move down that table over the line, just get incandescent as it is an ability for not having fought and look up whatever is relevant what depends on wounds. It says nowhere you get the other bonuses...
And incandescent turn 2 on a first charge is already pretty painful in my book cause those re-rolls will hurt.