The mixed results ordering is changeable on the General Options -> Ordering panel. Make sure you drag the post_page_cpt item to the top like so: https://i.imgur.com/CR5IG4n.png
However, the product might still appear on the bottom of the post type group list. In that case the only solution is to add one line of code to the plugin to override that ordering.
Open up the wp-content/plugins/ajax-search-pro/includes/search_content.class.php file and go to line 1509, where you should see this:
ksort( $pageposts['items'] );
Make a new line right after that one, and put this there:
$pageposts['items'] = array_reverse($pageposts['items'], true);
That should do the trick. Sorry about the complicated solution, but the grouping part of the plugin was made a long time ago, and it's a bit messy at the moment 🙂Best,
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