Address field "Same as above"
There is no simple solution, and therefore I'm not sure this question is good for the Drupal Stack Exchange. It's going to be a matter of custom JavaScript or AJAX Form API code, and it will be dependent on how you're using Address Field and what sort of form you're integrating it into.

Based on the comments below, though, I'd add that there's nothing particularly challenging about this. If both sets of form elements are on the same page, it's a simple matter to use JavaScript (especially with jQuery) to copy the data from one form field to the next. There just isn't a simple property to toggle within the form API code itself.