...that I would clarify is that it is really the switch to the chronometer cal. 1560 movement in the 5512 ca. late 1962 that precipitates the creation of the non-chronometer 5513, which actually was produced with the old cal. 1530 until around 1964-5. The 5513 gets the newly created, specifically non-chronometer 1520 ca. 1964 and the 5512 gets the updated SCOC 1570 a year later, '65.