Wasn't hybrid snipers, hybrid gunslingers. Shock charge(IP) for gunslinger also counts toward wounding shots(cull), so a hybrid gunslinger could hypothetically just use say vital shot(Corrosive dart) and shock charge then wounding shots and still have the full effect. When all 3 dots are applied however wounding shots still only uses 2 dots.
Sorry for pub terms, I use them because it only applies to them, or at least that is what I was told