Your sarcasm is noted.
I understand your only going to allow between September,14AD to September 15AD to mean in the first year of his reign. So only between September 28AD to September 29AD to mean in the 15th year.
Actually, no.
We have two options.
1. The actual 1st year of his reign was Sep 14 AD to Sep 15 AD. That was, literally, the 1st year of his reign.
2. If you were speaking of years and not his reign, then you could say 15 AD was the 2nd year.
But those are the only two options. It is impossible for 14 AD to be the 2nd year of his reign because his reign did not start until 14 AD.
So in the 15th year of his reign is actually 28 AD to 29 AD.
But if we are using his reign to denote calendar years then the 15th year on which he reigned would be 28 AD.
Either way 30 AD is too early for the crucifixion. The earliest possible year (if John is correct) is 31 AD. I lean towards 33 AD with a 3.5 year earthly ministry.