Yea Nofox, I had like 5k kills when I reached lvl50. So only place I could get kills was STS-25. Out of my 213k kills I did farm my last 20k kills in cycorps when the kills event was first time enabled. But farming cycorps was not fun. The only thing worth spending time in this game for me was farming in STS-25. I would have continued that way but others would eventually catch up farming low levels, hence I stopped. I am 99% certain the kills will now stay forever because disabling them again will be like repeating the same mistake.