[kh99]

Maybe something like this: create a plugin using hook location postbit_display_complete and code like:

if ($post['posts'] > 0)
{
    $post['tip_ratio'] = vb_number_format($post['reputation'] / $post['posts'], 1);
}
else
{
    $post['tip_ratio'] = '--'; // shouldn't ever happen, but protect against divide by 0.
}

Then use {vb:raw post.tip_ratio} in your postbit or postbit_legacy template.