You seem to be correct - I can only find three CoProcessors. When I duplicate your settings, and re-gen the map, it produces the same thing.
However, this is actually a Good-for-humans bug. The last CoProcessor on the map gives the AIP reduction when you kill it, not the 4th one. In other words, in this galaxy, when you kill the third CoProc, you get the -120 AIP. However, since you only had to kill 2 other CoProcs, you get a net of -80 AIP, rather than the normal net of -60 AIP.
Congrats?