Hi Dhilipan,
Point no 1 : I have assigned licnese manually to Material 20 in GTS. Determination of the license took place like it should be. (Issue solved)
Point no. 2 : Yes. System did allow me to create delivery even though order was in license block. Where as this is happening for few sales orders.
Point no. 3 : Cleared.
Regards,
Ashutosh