User blog comment:RemosPendragon/Chapter size/@comment-8395098-20150201151004/@comment-3053446-20150201155340

But that kind of throws out The Tank Commanders and the crew seen on the models. (http://wh40k.lexicanum.com/wiki/Antaro_Chronus)

Who is known as one of the tank commanders. It is possible there is an Astartes Commander in each hardline battle tank. As Predators were known to have three astartes in it. One Driver, One Gunner and one tank commander