I use warm ball rounds (S&B for me) for the same reason (I've written too much on that already - search here for "Erich" and ".380" if you want to read more) that I use them in the ballistically similar .380. I've worked on more 9x18 killings than .380 killings, interestingly, owing largely to the influx of PA-63s in the mid-'90s.