Why we don’t just call it as ‘Makkah‘ time instead of ‘alternative‘ prayer time?
It is because the alternative prayer time is not solely Makkah time. In fact it is combination between local time and Makkah time and more over there is also transition period in between. Local time is applied when there is perfect day and perfect night. Makkah time is applied when there is no perfect day or perfect night. And transition period is adopted to gradually connect between Makkah time and local time.