Duels description.

http://atwar-game.com/home/faq.php?faq_id=40

'The calculation of the SP rewards is similar to CP in Coalition wars and depends on the difference between the SP of the opponents. Minimum is 1 SP, maximum is 500 SP. Here's the formula:
(loserSP/((player1SP+player2SP)/2))*200'


We got ELO ratings so it's not the same formula anymore.