Gaining value in attack should be hardcoded impossible. A stealer may have more then 100% efficiency against other ships, but this should only play a role when ziks selfcover themselves in order to break even on salvage. See
this thread regarding zik in defense.
Edit: My argument is: I dont see any reasons for why gaining value should be possible, it encourages farming and fleetcatching of less active planets. It has also been abused to gain personal ranks several times, and often plays a role in the planet win.
This has nothing to do with ziks ability to steal other races ships, which obviously cant change.
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