Here the monitor displays the period-end-date of 2015 and 2016 as 26-09-2015 and 24-09-2016, respectively. Does this mean the formula above lets data be pulled out at any point in time from 27-09-2015 to 24-09-2016? Besides, is my understanding correct that the calendar year 2016 is from 27-09-2015 to 24-09-2016?
Calendar year starts on the 1st of January and ends on the 31st of December:
What you are referring to, I am guessing, is Apple's fiscal year end, which is the 30th of September:
For instance, try this:
df, e = ek.get_data("AAPL.O", ['TR.TRESGScore.date', 'TR.TRESGScore'], {'Period': 'FY0', 'SDate':'-10', 'EDate':'0'})
I suggest you double-check this with your local Refinitiv support desk, but please make sure your question is about Eikon Excel and TR function, which somewhat equivalent to ek.get_data.