Why don't AM or PM appear on my emails?

Question

I set my Mac to 24 hour clock. It works perfectly in my lists of emails sent and received, but the times displayed on actual emails are ludicrous. Examples:
01:59 shows as 1:59:16
16:22 shows as 4:22:00
My desire is to have the emails showing 24 hour clock time. Logically, having set the system thus, I'd expect that to occur. Can anyone help me with a solution, or is it bad programming?
Alternatively, I could live with the times shown on emails, provided that AM or PM showed too. I tried to achieve that, without success. Here's what I did:
System Preferences>International>Formats>Customize. Then I made the following selections:
* Short. (So why are seconds showing on emails?)
* 01-24.
* Before noon: AM.
* After noon: PM. (I reinstated the AM & PM after I didn't get 24 hour times on my emails.)
I should be very grateful if somebody could advise me how to get AM & PM back. As shown in the two examples early in this posting, 12 hour times without AM or PM are totally confusing. How to kill seconds would be a bonus, but I can live with seconds.
Please, when replying to me, no "computer speak". I'm new and should be grateful for blow by blow instructions.
20" iMac Intel Core 2 Duo   Mac OS X (10.4.10)  

Answer 1

Thanks for your latest response, David. I'm going to reply to your queries, in the order in which they appeared in your posting.
Q: Does the problem persist if you quit Mail and open it again?
A. Yes. It has persisted for many days, with nightly computer shutdowns.
"> surely the Short choice means no seconds?"
Your first paragraph stated that having the Short option chosen "has absolutely no effect on whether applications will use it for displaying date & time information." That leads me to advise you how I achieved 24 hour time in Mail. I followed the advice of Michael Lafferty in the iCal forum, about how to achieve 24 hour time in iCal. It worked and, as a bonus, gave me 24 hour time in the Mail message list. Unfortunately, it gave the crazy, inconsistent times on emails, which are the topic of this thread. Michael was answering the topic "24 Hour times in iCal" and the posting was at 6:42 PM on Feb 18, 2006. Here it is:
This is a goofy Mac OS X 10.4 thing.
Launch System Preferences and open the International preference pane in the Personal panel. Press the Formats tab and then the Customize… button in the center, under the Times section.
Under the Show: Short menu, you should see two values listed, the first representing hours, and the second representing minutes. If you click on that first value, you should see a downward-facing triangle. Press it to drop-down a menu on the right hand side of the value, and select the 01-24 format choice. Press the OK button, and quit.
iCal should display 24 hour times from that point on, though some users—all or most using releases prior to version 2—indicating that existing event times don't shift to 24 hour representation. All of mine did.
PowerBook G4 12 867 MHz 640 meg 40 gig SuperDrive Mac OS X (10.4.5) paired with a Treo 600 on the T-Mobile network
End of quote.
Knowing the above may help you to determine what happened. It may also make your third paragraph question redundant, but I shall answer it , in case it is still relevant. I dragged the Mail display so wide that it took up the complete width of the Mac's screen. The time display was unchanged. It continued to hug the right hand side of the display, but with lots of empty space between it and the previous column.
Returning to my problem, I was concerned that recipients of my emails would get the ambiguous and confusing times shown in para. 2 of my original posting. However, today a friend sent me a reply including my original message. Instead of showing the ambiguous time that was on my version of the email, it had it nicely expressed as a PM time.
While I'd prefer that unambiguous times appeared on my version of emails, ( that is, as shown on my screen, ) I could live with garbage times, if I were sure that recipients would receive 24 hour, or AM/PM style times.
So, my acceptable solutions, starting with my favourite, are as follows:
1. 24 hour clock on my version of emails and on the recipients'.
2. AM/PM on mine and the recipients'.
3. Ambiguous on mine, provided I could be sure that recipients would receive intelligible times. My message list would show the correct times.
I do realise that I could revert to AM/PM in iCal and in my Mail message list, if none of 1 to 3 were possible.
I suspect that you're like me: like to resolve a problem! I suspect that I've given you a juicy one here and I really appreciate your help.
20" iMac Intel Core 2 Duo   Mac OS X (10.4.10)