Knowledge hacking is a little special in that by the time you've started to do it, you've already succeeded, basically. Having the hacker wiped out at 1,500 Knowledge isn't a failure, it's 1,500 successes out of a possible 3,000 against the same planet.
The cost goes up for every 3,000 units hacked, so if you hacked hypothetical planets Murdoch and Lamothe for 1,500 each you'd still be going up a cost tier.
brb adding Lamothe to my altplanetnames