And you are sure the switch is not dialed to -3?
I use +/-0, center weighted AF (this influences the flash exposure, ettl tries to expose the subject on the focus point) and M mode with ISO 100. Post an image of your bulkhead wiring - maybe you did something wrong?
Yes, and I hated it. Watching a clown feeding beautiful animals to entertain 20+ divers in 10m water is not the way i like to dive. One reason that I will never dive on the bahamas again...
The amount of shots you can take on digital is just the biggest factor of all. I routinely shoot 20-40 shots of one subject in a ten minute period and still have plenty of room left for the next 50 mins of my dive.
Interesting, my amount of quality pictures increased after limiting myself to 20 pictures/dive.
Look, think, look again, shoot.
340 pictures/dive is just crazy. He should have a look at a video setup...