For outlaw necro rogue in 2+ targets, Hekili does not suggest to use Serrated Bone Spike on the targets which do not have the DoT. Instead, it just suggests to use Sinister Strike. I believe APL suggests to cast SBS as soon as possible to the targets in cleave if it does not overcap CPs.

PUT SNAPSHOT LINK HERE: https://pastebin.com/ciQgrxST

After you submitted your ticket, I set up Serrated Bone Spike to work with target cycling. You have to have Recommend Target Swaps enabled for your specialization for that to work (otherwise, the addon is following your preference of not telling you to use abilities on other targets).