On the 12z timer screen (1 or 2) to the right of the selected time
there is an arrow box with either a up or down arrow.
This is not shown in the manual nor on any update pdf.
What does this do when selected either up or down ?

count up or count down
as set in the settings for that timer.

No, timer count up or down is on the left hand side as a text box.
This other is a arrow on the right.

It looks like it does nothing. Likely a remnant from initial programming that's still there.

Found it in the 1.6 update.

Timer
Alarm mode
A mode which sounds an alarm every minute
during the remaining time up to the timer alarm
time has been added.
1. Open the Timer screen.
2. Change the setting by pressing or button.
 : An alarm sounds every minute of the elapsed
time from timer start. (Conventional mode)
 :An alarm sounds every minute of the
remaining time up to the alarm time.

How about that! There's so much that gets forgotten with these systems since they have so much to offer. We likely knew it when it came out, but it got forgotten with all of the other updates on the other systems. Thanks a lot!