diff --git a/booking.emails.inc b/booking.emails.inc
index 7bb08dd..31d2161 100644
--- a/booking.emails.inc
+++ b/booking.emails.inc
@@ -127,9 +127,9 @@ function _booking_balance_payment_email($nid)
 	$node = node_load($nid);
 	$tokens = booking_define_personspecific_tokens($node);	
 
-	if ($tokens['amount-owing'] <= 0)
+	if ($tokens['payment-required'] <= 0)
 	{
-		watchdog('booking', "Not sending amount owing email, since this person doesnt owe any money: @info", array('@info' => var_export($node, TRUE)));
+		watchdog('booking', "Not sending amount owing email, since this person doesn't owe any money: @info", array('@info' => var_export($node, TRUE)));
 		return;
 	}	
 
diff --git a/booking.install b/booking.install
index 2e02960..0f7cb11 100644
--- a/booking.install
+++ b/booking.install
@@ -136,6 +136,26 @@ function booking_update_7202() {
 	//user form to register for a given variety session
 }
 
+/**
+* Add tables for study group calculations
+*/
+function booking_update_7203() {
+	
+	//TODO: Figure out what fields we need
+	$booking_studygroup_mapping = array(
+		'fields' => array(
+			'sid' => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE, 'disp-width' => '10'),
+			'booking_eventid' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'disp-width' => '10'),
+			'booking_node_id' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'disp-width' => '10'),
+			'booking_studygroup_id' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'disp-width' => '10'),
+			'booking_is_leader' => array('type' => 'varchar', 'length' => '1', 'not null' => FALSE),
+			'booking_is_helper' => array('type' => 'varchar', 'length' => '1', 'not null' => FALSE),
+		),            
+		'primary key' => array('sid'),
+	);
+	
+}
+
 /**
  * Implementation of hook_install().
  */