diff --git a/index.php b/index.php
index ad5cd11..b06d8d8 100644
--- a/index.php
+++ b/index.php
@@ -106,13 +106,13 @@ if (!$tpl_done && isset($_SESSION['access_token']) && $_SESSION['access_token'])
                 $data['action_uc'] = ucwords($action);
 
                 $fd = new FieldDefinition($action);
-                $fd->addFieldValues($_SESSION[$skey]);
+                $fd->setFieldValues($_SESSION[$skey]);
                 $fieldData = $fd->getFieldData();
                 $fields = $fieldData['fields'];
 
                 $data['email_date'] = date('r');
                 $data = array_merge($data, $fields);
-                $mo->addTemplateVars($data);
+                $mo->setTemplateVars($data);
                 $mo->setSubject('[FRS] ' . $data['action_uc'] . ' Reservation');
                 $mo->addRecipient($data['user']['email'], $data['user']['name_first'] . ' ' . $data['user']['name_last']);
                 $mail_sent = $mo->send();
@@ -144,7 +144,7 @@ if (!$tpl_done && isset($_SESSION['access_token']) && $_SESSION['access_token'])
                 $action = 'rentalcar';
                 require 'prep_form.php';
                 break;
-              default:
+            default:
                 if (!$tpl_done) {
                     $ho->setTemplate('loggedin_html');
                     $tpl_done = true;
@@ -160,5 +160,5 @@ if (!$tpl_done && isset($_SESSION['access_token']) && $_SESSION['access_token'])
 
 $data['action'] = $_GET['action'];
 
-$ho->addTemplateVars($data);
+$ho->setTemplateVars($data);
 $ho->sendOutputToStdout();
diff --git a/lib/Frs/FieldDefinition.php b/lib/Frs/FieldDefinition.php
index a9517a1..c070561 100644
--- a/lib/Frs/FieldDefinition.php
+++ b/lib/Frs/FieldDefinition.php
@@ -124,17 +124,22 @@ class FieldDefinition
     }
 
     /**
-     * Adds a placeholder token and the desired replacement value.
+     * Sets a placeholder token and the desired replacement value.
      *
      * @param string $placeholder Placeholder, e.g. USER_NAME
      * @param string $replacement Replacement value, e.g. John Doe
      */
-    public function addPlaceholder($placeholder, $replacement)
+    public function setPlaceholder($placeholder, $replacement)
     {
         $this->placeholders[$placeholder] = $replacement;
     }
 
-    public function addPlaceholders($placeholders)
+    /**
+     * Sets multiple placeholders and their values.
+     *
+     * @param array $placeholders Associative array of placeholders and values
+     */
+    public function setPlaceholders($placeholders)
     {
         $this->placeholders = array_merge($this->placeholders, $placeholders);
     }
@@ -150,12 +155,11 @@ class FieldDefinition
     }
 
     /**
-     * Adds the given $values or default values and replaces $placeholders. Also
-     * adds some helping attributes to fields.
+     * Sets the given $values for the given fields.
      *
      * @param mixed[] Key-value-array of values (value) to assign to fields (key)
      */
-    public function addFieldValues($values = array())
+    public function setFieldValues($values = array())
     {
         foreach ($this->fieldData['fields'] as $key=>$meta) {
             // Assign session value if set, or use default if set
diff --git a/lib/Frs/Output/GenericOutput.php b/lib/Frs/Output/GenericOutput.php
index 0fb3dd1..84ce1f7 100644
--- a/lib/Frs/Output/GenericOutput.php
+++ b/lib/Frs/Output/GenericOutput.php
@@ -33,12 +33,12 @@ class GenericOutput
         $this->template = $this->templateEngine->loadTemplate($templateName);
     }
 
-    public function addTemplateVar($key, $value)
+    public function setTemplateVar($key, $value)
     {
         $this->templateVars[$key] = $value;
     }
 
-    public function addTemplateVars($tplVars)
+    public function setTemplateVars($tplVars)
     {
         // maybe use array_merge_recursive one day... but currently I think this is better
         $this->templateVars = array_merge($this->templateVars, $tplVars);
diff --git a/prep_form.php b/prep_form.php
index 1ea5a6a..86fdcfb 100644
--- a/prep_form.php
+++ b/prep_form.php
@@ -15,8 +15,8 @@ $placeholders = array(
     'USER_NAME'  => $data['user']['name_first'] . ' ' . $data['user']['name_last'],
     'USER_EMAIL' => $data['user']['email'],
 );
-$fd->addPlaceholders($placeholders);
-$fd->addFieldValues($_SESSION[$skey]);
+$fd->setPlaceholders($placeholders);
+$fd->setFieldValues($_SESSION[$skey]);
 
 $by_group = $fd->getGroups();
 
diff --git a/tests/FieldDefinitionTest.php b/tests/FieldDefinitionTest.php
index c4da5af..d4aee49 100644
--- a/tests/FieldDefinitionTest.php
+++ b/tests/FieldDefinitionTest.php
@@ -34,8 +34,8 @@ class FieldDefinitionTest extends \PHPUnit_Framework_TestCase
     public function testAddFieldValues()
     {
         $fdo = new FieldDefinition('hotel');
-        $fdo->addPlaceholder('USER_NAME', 'John Doe');
-        $fdo->addFieldValues(array('url'=>'http://example.org/'));
+        $fdo->setPlaceholder('USER_NAME', 'John Doe');
+        $fdo->setFieldValues(array('url'=>'http://example.org/'));
         $fd = $fdo->getFieldData();
         $this->assertArrayHasKey('fields', $fd);
         $this->assertArrayHasKey('url', $fd['fields']);
@@ -47,7 +47,7 @@ class FieldDefinitionTest extends \PHPUnit_Framework_TestCase
     public function testSupportValues()
     {
         $fdo = new FieldDefinition('hotel');
-        $fdo->addFieldValues(array('modifiedTime'=>'2016-01-01 01:01:01'));
+        $fdo->setFieldValues(array('modifiedTime'=>'2016-01-01 01:01:01'));
         $fd = $fdo->getFieldData();
         $this->assertArrayHasKey('today', $fd['fields']['modifiedTime']);
         $this->assertEquals(date('Y-m-d'), $fd['fields']['modifiedTime']['today']);
@@ -57,7 +57,7 @@ class FieldDefinitionTest extends \PHPUnit_Framework_TestCase
     {
         ini_set('date.timezone', 'Europe/Berlin');
         $fdo = new FieldDefinition('hotel');
-        $fdo->addFieldValues(array('modifiedTime'=>'2016-01-01 01:01:01'));
+        $fdo->setFieldValues(array('modifiedTime'=>'2016-01-01 01:01:01'));
         $fd = $fdo->getFieldData();
         $this->assertArrayHasKey('value_unixtime', $fd['fields']['modifiedTime']);
         $this->assertEquals(1451606461, $fd['fields']['modifiedTime']['value_unixtime']);