Perhaps they counted dealer demo cars or there were unwind deals. Meaning someone bought it on the 28 of FEb, didn't get financed or brought it back for some reason in March. Now it is reported as sold in Feb, and then subsequently sold again as new in March to the next guy. If it was never registered, it wouldn't show as used and would end up sold as twice. I got a good deal on a Nissan Versa that way, hadd 1100 miles, but was still considered a new car.