You beat me to it. I know that one time, a long, long, long, long, time ago, Shaq really had his body fat down to an insane %. But for most guys that weigh over 280, 16% isn't that unusual. I mean it could and probably will get better, but its certainly not cause for alarm.
I always get a kick out of when people compare verticals. And they'll compare a player, ususally a guard with a 38' or 40", to a guy like Cousins who may have a 28" vertical ( I just made that up. I don't know the results yet). To that I say, let me hang another 6o or so pounds on the guard and see how high he jumps.
By the way, it looked like Monroe didn't get more than 6" off the ground when I was watching him do the standing vertical. I'm sure it was more than that, but thats how it appeared on Televison. Good thing he's tall with a good wingspan, because he's definitely vertically challenged.