OST went all Pioneer?

Looked at his commanders and I assumed he would go Ostruppen, so I wanted mg and mortar to bleed and slow him down.
Little did I know, he went with Ostruppen Commander but only made Pioneer.

Start the game 2 engi to clown car to try and bleed his ostrupp before they fight with Penals. As I am capping I see he pushes my cutoff with 2 pioneers which I fight back with using car and 2 engi. Beat them back repair and fight yet another Pioneer squad. On the other side my penal almost got wiped by 2 pioneers. At this point I am wondering what the hell is going on. He pushes my cutoff again with 3 i think but I caught him unaware and got a satchel wipe. I am now hiding my clown car since he is most likely rushing a Scout car which comes out at about 5 mins. At this point I have an mg and just punish him back and control decent map so I flank him with Penal squad and rush his scout car. He was trying to build a 2nd but I think he felt it would go the same way since he has no way to push me back.

GG

Weird build that might have worked if I went with standard Conscript opening. Doubling a conscript squad would be devastating.
Also assuming he was going to use call in for team weapons but he was losing to much for it to work out.

Anyone else see someone try this.