So, basically the same as switching targets with a Heavy Machine Gun.
No, Apparently everyone is misreading what he is saying.
on the field is a AA HT, a Grenadier Squad, and a 222. The AA HT is currently engaging the grenadier squad, the 222 drives up on one of the sides of the grenadier squad, but still INSIDE THE AA HALFTRACKS CONE OF FIRE, the player tells the AA HT to switch targets to the 222 - instead of just rotating its gun like a HMG team would, it turns its entire chassis resetting the time it takes for its auto-cannon to start firing again.
In a different situation where the AA HT kills the grenadier squad as the 222 shows up and switches targets by itself its auto-cannon will continue firing (if it still has ammo in clip).
I haven't had an issue with it but I can see where he is coming from.