stellte 30 vnZ den ägyptischen Kalender auf den julianischen Kalender um. This is not for sure (see Parkers Egyptian Calendars, p.70, n.6), he follows Snyder for 30BC.
A good overview and discussion in
http://www.gnomon.ku-eichstaett.de/LAG/kalender.html I think about the foundation of the Alexandrian Calender you have to consider that >from 46BC up to 30BC were made false (too much) intercalations regarding the calendar reform of Julius Cäsar.
In 8BC Augustus corrected these errors.
In the calendar calculation the ideal relations are considered: 29.08.30BC=4.Epagomentag; 29.08.25BC= 1.Thot