I made the suggested change to the code and I'm still not seeing conversion data on the invoice page. Here is my changed code:
//Commented out $smarty->assign('ga_track_commerce', $ga_track_commerce);
$ga_track_commerce = 'Y'; //Change from 'N' to 'Y' based on http://forum.x-cart.com/showpost.php?p=357851&postcount=3 (12/22/2014)
$ga_async_commerce = "N";
I had tried changing the Async part to 'Y' as well but it did not help, and I changed it back because it wasn't mentioned here originally. Any other ideas?