I hope you know this discussion wasn't aimed at you. It was just an aside, since it comes up often from people.
The iPhone app is $10. I think it's well worth it. The Mac app can do more than the iPhone app, but I don't bring a computer when I travel. One of the coolest things about the iPhone app, I think, is the location tracking. Turn it on, throw your phone in a dry bag, and go diving. It will keep marking your location, so after you're done diving, you can turn off the tracking, sync your Teric, and each dive, based on the start time, will have the coordinates from the tracking so all you have to do is name the site and you're set. There it is on your map.
I really don't think you need the family plan if you're the only one using it.