I see. That will be confusing to non-americans to whom a 12-hour clock is far from standard. It's also seems a bit weird to have two checkboxes (= 4 bits of information) to choose between a 12-hour and 24-hour clock (2 bits). I guess only one can be checked at a time?

That said, however, what you probably should be doing is to respect the setting in iOS: http://i.imgur.com/kMQgw3m.png

Sorry for the OC. I may have missed something here. I don't see how two checkboxes equal 4 bits of information by default. In this case you can have two checkboxes depending on 1 bit that can represent and/or count 2 values regardless the two checkboxes being complementary or contrary. Four bits can represent up to 16... Are you referencing "bit" for "piece" and also for "binary digit" ? Other ?

Err... my brain was just malfunctioning. I meant to say 1 bit and 2 bits, not 2¹ and 2² bits. :-)

Thanks for posting back, that was driving me insane. :D

Definitely more efficient. You are right, I will change it.