diff --git a/src/Spout/Writer/Common/Helper/AbstractStyleHelper.php b/src/Spout/Writer/Common/Helper/AbstractStyleHelper.php
index 77a6b93..372ef62 100644
--- a/src/Spout/Writer/Common/Helper/AbstractStyleHelper.php
+++ b/src/Spout/Writer/Common/Helper/AbstractStyleHelper.php
@@ -34,7 +34,7 @@ abstract class AbstractStyleHelper
      */
     public function registerStyle($style)
     {
-        $return = [];
+
         $styles = is_array($style) ? $style : [$style];
 
         foreach ($styles as $style) {
@@ -43,10 +43,15 @@ abstract class AbstractStyleHelper
             if (!$this->hasStyleAlreadyBeenRegistered($style)) {
                 $nextStyleId = count($this->serializedStyleToStyleIdMappingTable);
                 $style->setId($nextStyleId);
+
                 $this->serializedStyleToStyleIdMappingTable[$serializedStyle] = $nextStyleId;
                 $this->styleIdToStyleMappingTable[$nextStyleId] = $style;
             }
-            $return[] = $this->getStyleFromSerializedStyle($serializedStyle);
+        }
+
+        $return = [];
+        foreach ($this->serializedStyleToStyleIdMappingTable as $serializedStyle => $styleId) {
+            $return[$styleId] = $this->styleIdToStyleMappingTable[$styleId];
         }
 
         return $return;
diff --git a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
index 1d0c7a5..46a73e7 100644
--- a/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/ODS/Helper/StyleHelperTest.php
@@ -35,7 +35,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $this->assertNull($style2->getId());
 
         $styleHelper = new StyleHelper($this->defaultStyle);
-        $registeredStyles = $styleHelper->registerStyle([$style1, $style2]);
+        $registeredStyles = $styleHelper->registerStyle($style1);
+        $registeredStyles = $styleHelper->registerStyle($style2);
 
         $this->assertEquals(1, $registeredStyles[0]->getId());
         $this->assertEquals(2, $registeredStyles[1]->getId());
diff --git a/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php b/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
index 30d7031..cc59fbb 100644
--- a/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
+++ b/tests/Spout/Writer/XLSX/Helper/StyleHelperTest.php
@@ -35,7 +35,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $this->assertNull($style2->getId());
 
         $styleHelper = new StyleHelper($this->defaultStyle);
-        $registeredStyles = $styleHelper->registerStyle([$style1, $style2]);
+        $registeredStyles = $styleHelper->registerStyle($style1);
+        $registeredStyles = $styleHelper->registerStyle($style2);
 
         $this->assertEquals(1, $registeredStyles[0]->getId());
         $this->assertEquals(2, $registeredStyles[1]->getId());
@@ -52,8 +53,8 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
         $registeredStyles = $styleHelper->registerStyle($style);
         $registeredStyles = $styleHelper->registerStyle($style);
 
-        $this->assertEquals(1, $registeredStyles[0]->getId());
-        $this->assertEquals(1, $registeredStyles[0]->getId());
+        $this->assertEquals(1, $registeredStyle1->getId());
+        $this->assertEquals(1, $registeredStyle2->getId());
     }
 
     /**