I had DM3 until my computer crashed and it worked satisfactorily. I had to load DM-5 on my new computer and now it shows every 2nd dive downloaded from my vyper at twice actual depth. I was afraid I was having problems with the vyper until I downloaded the dives into subsurface and they all showed normally. I don't know who designed the software, but if it won't work with their own computers, heads should roll.