[ad_1]
This is by design. Quote from the help page:
If you set the goal difference bonus to anything other than zero (default is zero), then this bonus is added to the scored points if the user predicted the correct winner and the user was right about the goal difference (e.g. result is 2-1 and the user predicted 3-2). This bonus is not rewarded when the user predicted the wrong winner (e.g. result is 2-1 and the user predicted 2-3), when already a full score was awarded or when the match result is a draw (e.g. 2-2).
/wp-admin/admin.php?page=footballpool-help#points
If you want it differently, then you may consider also installing this extension plugin.