@ aviator_prat
How silly of me. I had got the Real drift. But for 45 degree north, I was calculating with hourly real drift and 45 mins of ERW.
my incorrect equation :
Md = RD + ERW
= 7.5 (increasing) + 15 * sin45 * (45/60)
This caused the blunder.
Anyways Thanks. Any idea for the remaining 1 question