10's the max for all. Where it can be benificial to be above 10 is when he has a negative trait. 13 plus command vs minus 3 command still allows the general to be a 10 star. But if he has 12 positive command points and -3 command points he will be a 9 star. As far as influence 8 is the max allowed bonus for happiness and 9 and 10 only become a factor for senatorial offices/faction heir selection or the rare case a diplomat walks up to him and negotiates.