Hi Akhil
For futures there are three options to chose the closing. You can either have FIFO or LIFO. This can be assigned in the system as a standard procedure. You can also manually assign the closing transcation to an existing future transaction. In most cases customers use FIFO as a standard.
There is no possibility to assign a closing to the postion. The reason is that this has to happen according to the standard instruction you have with the broker. By the way in the P/L there is no difference as it will only change the realized/unrealized part in accounting.
Waited average closing for futures does not exist!
Kind regards
Juerg Heiz