Tl Dr: it's a dynamic point system that makes sure no one can accurately predict the point outcome of every siege:

1. Bounty point system: each player has his own reward system that is based on these factors: number of consecutive sessions, kdr, active player gap. With these inputed at the start of every session the player will either have a higher point reward when he is killed or a lower one if he hasn't been performing

2. Repeated kills on crafts: killing and sinking crafts of the same type will give more and more points for each one, this will give a chance of versatility in the meta and punish spamming the same craft over and over

3. Safe haven windows: each 24 hours each side can pick 2 windows where they have a safe window with no capping possible to combat night capping

Additionally I recommend adding a total victory condition: having a siege balance of +/-40k for 3 consecutive sieges automatically wins the siege for that side