Seviye atlama fonksiyonu fakat çalışmıyor. Sorun nerede ?

$UP_LEVEL2 = 100;
$UP_LEVEL3 = 500;
$UP_LEVEL4 = 1000;
$UP_LEVEL5 = 2500;
$UP_LEVEL6 = 5000;
$UP_LEVEL7 = 10000;
$UP_LEVEL8 = 25000;
$UP_LEVEL9 = 50000;
$UP_LEVEL10 = 100000;
$UP_LEVEL11 = 200000;
$UP_LEVEL12 = 300000;
$UP_LEVEL13 = 400000;
$UP_LEVEL14 = 500000;
$UP_LEVEL15 = 600000;
$UP_LEVEL16 = 700000;
$UP_LEVEL17 = 800000;
$UP_LEVEL18 = 900000;
$UP_LEVEL19 = 1000000;
$UP_LEVEL20 = 1500000;
$UP_LEVEL21 = 2000000;
$UP_LEVEL22 = 3000000;
$UP_LEVEL23 = 4000000;
$UP_LEVEL24 = 5000000;
$UP_LEVEL25 = 6000000;
$UP_LEVEL26 = 7000000;
$UP_LEVEL27 = 8000000;
$UP_LEVEL28 = 10000000;
$UP_LEVEL29 = 15000000;
$UP_LEVEL30 = 30000000;
$UP_LEVEL31 = 0;
$NEXTEXP = $AC_LEVEL + 1;
$LEVELCHECKS = "UP_LEVEL$NEXTEXP";
$LEVELCHECKST = $LEVELCHECKS;
@$EXPBAR = $AC_EXP * 100 / $LEVELCHECKST;
$LEVEL_GIFT = $CON_ULG * $NEXTEXP;
if($AC_EXP >= $LEVELCHECKST and $AC_LEVEL < 30){
mysql_query("UPDATE user_data SET level = level + '1' WHERE username = '".$AC_USERNAME."'");
mysql_query("UPDATE user_data SET balance = balance + '".$LEVEL_GIFT."' WHERE username = '".$AC_USERNAME."'");
mysql_query("INSERT INTO notification_data (username, note, date, icon, ip) VALUES ('".$AC_USERNAME."', 'Tebrikler! Seviye ".$NEXTEXP." Oldunuz ve ".$LEVEL_GIFT." ".$CON_MONEYNAME." Kazandınız.', '".$T_DMYHIS."', 'gift', '".$C_IP."')");
}