One indvidual that can answer this question is Fish Cafaro. From what i read from his testimony (but i didn't read everything), it was clear to Salerno that Gigante was the shot caller. Salerno didn't seem to have any negative feelings towards Gigante.

It also appears that somehow, Gigante made sure that Salerno was well informed on what was going on with the family and that he was included in the decision making. As stated above, Salerno was one of the best connected mafioso in the country and i feel that Gigante gave him some autonomy in how he would deal with other families.