Digging through old patch notes, I see that ion cannons above II and zenith energy producers once added a multiplier to waves against that planet. I also saw someone speculate that this was removed for ion cannons by version 5.0, but I don't see confirmation. Are there presently any hidden wave multipliers that you can have based on stuff on your own planet?
I prefer to set up choke points where I can capture an Ion Cannon IV, so...