This may sound like a stupid question but does Shooter recognize below sea level density altitude. The reason for asking is I was out shooting yesterday and my Kestrel showed a DA of in excess of -500 feet. I entered -500 into the DA box but the results were quite a bit off from I Snipe which I used the local conditions given online. ISnipe seemed to be more correct for the longer ranges and the Shooter data was off a bit. It seemed to be bang on during the summer months when I did not have to enter a below sea level DA. So by just entering -500 in the DA box, the program should give me relatively correct data assuming all the other parameters entered are correct? I did a search for this and got lots of info but nothing that answered my question. I may be out to lunch on this but was just wondering.