I've scored about two or three kills in a stock EC-89 govship(It isn't much of a bus these days) and noticed that my bushunter kills stayed at 18 kills with 32 more to go. I've tried several different scenarios that include dueling and other weapons, but none of them made any difference.

Has to be an ec-88.

It's supposed to work with the new EC-89.
It won't work with the old EC-88 anymore.