so the macchinator array allows you to fire its two weapons at the same time or one of them and another weapon the model already has.
cyberthurgy states 'may use a single power in the shooting phase instead of making a shooting attack'
battlesmith states 'they can attempt to repair one of them instead of firing a weapon'
key point here is 'a' - singular or generalized?
i like the idea of a magos taking cover behined a damaged vehicle and screwing with a nearby robot's programming while his macchinator array fixes things behind him/her/it.