Hi Meena
The system does not look on deals it looks on position for the closing. This is defined by the process where you define LIFO or FIFO or manual assignment. If you buy 100 @ 50, 100 @ 60 and 100 @ 70 you have an average of 300 @ 60. If you now sell 150 @ 80 and you have defined FIFO the system takes 100 @ 50 and also 50 @ 60 to calculate the realized gain. If you define LIFO the system obviously first takes 100 @ 70 and 100 @ 60 to calculate the realized gain.
Therefore the position is relevant and not the transaction.
Kind regards
Juerg Heiz