No see, that's my point. Sertorius is genuinely asking us for advice, because he is genuinely conflicted about what to do.
Possibly so- but if he weren't conflicted about it, he wouldn't be asking us for advice.
So it comes down to, are we counseling him to stick with the plan to conquer the Samnites, or to overstep his orders and destroy the Samnites for personal gain? Left to his own devices he might choose either outcome, of course.
I, for one, vote to counsel him to stick with the plan to conquer the Samnites, so that's what Plan Fidelis Constans does.
This strikes me as a really indirect way to 'support' Sulla.
If we were that interested in supporting Sulla, we probably shouldn't have informed on Pompey's plot.
[Also, given what 'And Call it Peace' does to the Samnites, decimation would be a kindness compared to what would really happen. Let's use words to mean what they mean...]