Oh, I guess I misinterpreted this from .67
"The mobile-builder-command-station-foldouts in multiplayer will now process per-planet auto-build controls (for engineer mkI,II,III, remains rebuilder, and energy reactor I,II,III) set by the owner of the foldout (not the owner of the planet)."
I took this to mean that my allies foldout (which are always on my planets, not his, since he as the actual building on his own planets) would process commands that he sets for per-planet autobuilding.