This ability appears to be performing damage as though it has 5 Combo points regardless of the number of combo points spent, instead of the +5 combo points the ability description states.
While my sample size is somewhat low:
7 point Dispatch:
Average 239k
Normal hit Avg: 185k, Min: 142k, Max: 212k
Crit hit Avg: 357k, Min: 331k, Max: 399k
7(12) point Coup:
Average 196k
Normal hit Avg: 111k, Min 83k, Max 189k
Crit Hit Avg: 257k, Min 163k, Max 403k
While there is some dice variance, I would expect an effectively 12 point finisher to always deal more than a 7 point one.