Breguet used ebauches(and not only for the souscription watches!),although the term should not be mixed up with our present idea of thousands of identical ebauches built by automatized process.His movements were all slightly differently and the ebauches he used were made by or for him exclusively and each being slightly different to stand up to his idea of individuality,but You are right the souscription-movements were an answer to a huge demand for "affordable" Breguet-watches.
Nr 689,the one Alberto has shown,or Nr 729,Nr 1623,Nr 987,Nr 1106 or the extremely beautiful Nr 2732 and 852 with blue enamel case are all interesting examples of the "souscription-line" as they sport the small hours-minutes dial at 12 as the new "Tradition" in Basel(plus the typical "a tact" palpable hours hand on the case),while most Souscription watches only had an hours hand.
Breguet did a lot of experiments too with these souscription-movements and even used Arnold lever escapements in some later ones of them.The movements quoted are early examples with ruby cylinder escapement,Nr 444 even sported an equation-hand!!(very extraordinary for a souscription watch)
Thus we see,although these early souscription-movements look very similar at first glance(reminding of our idea of ebauche usage)they were very different in details and Breguet was frequently playing with new ideas and inventions also on these cheaper watches.
regards,
Lutz