Success!

<data short="1012h-endash-hotkey" long="10{Ctrl -}12 hours" display="10-12 hours (Ctrl - hotkey)" />

I just noticed your entry was missing "12" in the "long" part, so I just edited my temp glossary as above.

Now, my expansions show as:

10-12 hours
10–12 hours
10–12 hours

So the last expansion is correctly showing the en dash!

Now, my remaining problem is I don't want my "Display as:" showing 10{Ctrl -}12 hours. Unless I manually edit each and every glossary "display as" how do I avoid this??