Initially when we installed the site on an older J3/VM3 site the plugin didn't do anything in the backend - it only gave a ton of javascript errors.
It turns out that the plugin simply wasn't loading a bunch of needed JS files at all.
In awocoupon.php line 174 we added the following lines to load those 4 missing files, and all was well.
$document->addScript( AWOCOUPON_ASSET_URL . '/js/coupon.js' );
$document->addScript( AWOCOUPON_ASSET_URL . '/js/jquery.dataTables.min.js' );
$document->addScript( AWOCOUPON_ASSET_URL . '/js/dataTables.select.min.js' );
$document->addScript( AWOCOUPON_ASSET_URL . '/js/dataTables.buttons.min.js' );
Kind of a big oversight on a commercial plugin.
Anyhow - FYI.