I just replaced the batteries in my DataMax II and used my fingers to take a quick dive to 20'. The displays showing me two sets of times (the second being the elapsed time) and the dive number. I'm unsure what the first time is. I figured after 5mins at the surface or something it would turn off, but it's been reassembled on my desk for sort of a while and it's still counting up my nine-and-a-half hour dive time. Does it stop at some point? Or did I confuse it by doing 20 feet for 3 seconds?