Here's the questions, both involving the Cobra:
1. The Cobra manual says that for a recommended safety stop, the "STOP" indicator should come on when you are between 10 and 20ft., and stay on while it counts down the 3 minute stop. But the STOP indicator doesn't always come on. Often it will just have the countdown number, but no "STOP" indicator.
2. The manual says that "with every dive over 10 meters (30ft.) the instrument has a 3 minute countdown for the recommended safety stop..." In fact, with some actual and simulated dives in the 30-40 ft. range, there is no safety stop indication (neither STOP nor countdown time).