zm, I almost always start a sentence with a cap unless the referent isn't upper case, such as "zm" or "tsu", though I might slip once in a while. As for final punctuation, this is a time-honored style, and if you flip through the pages of, e.g. a Time Mag, you will find many instances

It makes the writer seem less assertive, and if there's one thing you don't want to seem on WS, it's assertive. Also by the time I cash in I will have saved four million, three hundred and forty-five thousand, seven hundred fifty two keystrokes

Is there anyone on WS who doesn't recognize this sentence as a question

dalehileman