When I examined the ICM 1917-1918 German Assault Troops set, I noticed that the tunics do not seem to match any reference I've found. Of the different blouses I've looked at in various places on the Internet, none seem to have the scalloped lower pocket flaps on the tunic skirt that the kit has.
You're right; it's a straight flap in all types of uniform; in case of the stormtroopers the flap was often pushed to the inside in combat so that a better access to the spare rounds carried in the pockets was possible.
