Morgan
you wrote: "my Spot1 doesn't let you change modes from tracking to
sending an OK without powering it off first. "

I have a Spot 1 too.
I don't send OK messages during flight either, but I do switch off the
tracking mode at the end of flight and send another OK message without
powering off.
My standard procedure is as follows:
During pre-flight I power on the Spot1 and initiate an OK message. It
will blink the LED until the message has been send (message will be
transmitted 3 times I believe).
Before take-off, when the LED has stopped blinking for the OK message,
I push the OK button long to initiate the tracking mode. Push as long
until the green LED comes on.
After landing, I again push the OK button long to stop the tracking
mode. I push as long until the RED LED comes on. Then it takes a few
seconds for the Spot 1 to terminate the tracking process and then the
LED is off.
A short push of the OK button then initiates the final OK message.

The problem I have is that I cannot terminate the OK message without
powering off to get to the tracking mode.
This is relevant when there is too little time between pre-flight and
launch, i.e. when to OK message LED has not yet stopped blinking and
you want to switch to tracking mode (you are not sure if the OK
message really completed).

3U