FWIW, in Swedish it's perfectly normal to say the leading zero on hours, to use the "xx hundred" construct when buying twelve hundred grams of minced meat, as well as to refer to years after 2000 as "twenty hundred and fifteen" (tjugohundrafemton). I think the reason the post uses the "twelve hundred hours" is because the American military does.

That said, I agree that there's nothing awkward about 24 hour times.