So completing Cass's companion quest 'Heartache by the numbers' looks like it has a revenge option and a law and order option that offer different perks. Anyone know what they are/do?

Revenge gives a perk that increases her skill with Guns. Not sure about the law and order one.

I had a problem with this... b/c I did it out of order. I took her to "talk" to the Van Graffs, trying to do their questline, but when they wanted to kill her I told them they better not and they turned hostile so I killed them. Killing the Van Graffs was apparently part of her personal quest so when it was time to kill off the crimson caravan dudes...by "settling accounts" ... it didn't register that I killed alice mclafferty.