Issue with the Assassination Rogue APL

I was looking through the Assassination Rogue APL and notice that it is recommending to refresh rupture at 5 combo points, (without Exsanguinate selected) as well as to mutilate at 4 combo points. Is this an error or is there something I’m not aware of? The conventional wisdom is to Mutilate until you obtain 4+ Cps and then use finishers as appropriate.

You can use Rupture at 4 combo points if you want, it won’t lower your DPS. Waiting for 5 combo points (even if that means using mutilate at 4 cp) won’t lower your DPS either. This is a case where you could do it either way and never notice a difference. In reality, the number of times you end up at exactly 4 combo points when you need to refresh rupture is pretty low.