Their older computers required you to send it back in for a battery change periodically. This was a set time based on an average person's # of dives and length of dives. So the actual battery usage icon doesnt really work past a certain point! It's not accurate when the battery life is low-er. It jumps from 1/3 to 0! My buddy's computer showed ERR mid-dive b/c his battery died! It was showing battery at 30% during the previous surface interval.

He sent it in and instead of replacing the battery, they gave him a new one saying that it was designed to NOT fail underwater.

Send yours in, I'm sure they will check it out for you