Interestingly open source on-line piece on Arrian
https://www.cambridge.org/core/journals/greece-and-rome/article/stealing-victory-at-gaugamela-the-manipulation-of-time-in-arrians-narrative/75E7BBB9CC84D6E995F9415674F6C935?utm_source=SFMC&%3Butm_medium=email&%3Butm_content=Article&%3Butm_campaign=New%20Cambridge%20Alert%20-%20Issues&%3BWT.mc_id=New%20Cambridge%20Alert%20-%20Issues
someone has gone into great depth to tease this out and very interesting indeed