I believe that "service failure" is a factor in determining what truck gets the load, but I don't know if it is more important than acceptance rate.
We're working from memory and may be wrong. But as we think back to the Contractor Helper book that FCC gave us years ago, and to the section that explained the criteria the computer used to select trucks, Diane and I do not recall seeing anything about service failures being figured into the program one way or another.
Certainly the company has some publication somewhere that explains how the system works today, right? They did at one time, at least. That's half the battle for someone who wants to understand the rules. The other half is having the confidence that there is but one set of rules and they are followed the same for each truck in the fleet.
We had that confidence most of the time we were with the company but it faded as we saw exceptions being increasingly made and then outright policy changes being made but not announced about one set of rules applying to some trucks and another set applying to others (preferential dispatch). That was what motivated us to leave FCC in 2010.
It is a good thing that this policy was announced. That's a step forward compared to how it used to be. Hopefully, the company will be as forthcoming in answering the questions the announcement is raising as it was in making the announcement in the first place.
Simple fairness and the desire to "do the right thing" (a popular phrase in corporate culture these days) would compel the people in charge to explain clearly and exactly how the system works for the different kinds and groups of trucks in the fleet.