diff --git a/Classes/PHPExcel/Calculation/TextData.php b/Classes/PHPExcel/Calculation/TextData.php
index 3c3ed22..d08829c 100644
--- a/Classes/PHPExcel/Calculation/TextData.php
+++ b/Classes/PHPExcel/Calculation/TextData.php
@@ -440,11 +440,7 @@ class PHPExcel_Calculation_TextData {
 			$mixedCaseString = ($mixedCaseString) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
 		}
 
-		if (function_exists('mb_convert_case')) {
-			return mb_convert_case($mixedCaseString, MB_CASE_LOWER, 'UTF-8');
-		} else {
-			return strtoupper($mixedCaseString);
-		}
+		return PHPExcel_Shared_String::StrToLower($mixedCaseString);
 	}	//	function LOWERCASE()
 
 
@@ -463,11 +459,7 @@ class PHPExcel_Calculation_TextData {
 			$mixedCaseString = ($mixedCaseString) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
 		}
 
-		if (function_exists('mb_convert_case')) {
-			return mb_convert_case($mixedCaseString, MB_CASE_UPPER, 'UTF-8');
-		} else {
-			return strtoupper($mixedCaseString);
-		}
+		return PHPExcel_Shared_String::StrToUpper($mixedCaseString);
 	}	//	function UPPERCASE()
 
 
@@ -486,11 +478,7 @@ class PHPExcel_Calculation_TextData {
 			$mixedCaseString = ($mixedCaseString) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
 		}
 
-		if (function_exists('mb_convert_case')) {
-			return mb_convert_case($mixedCaseString, MB_CASE_TITLE, 'UTF-8');
-		} else {
-			return ucwords($mixedCaseString);
-		}
+		return PHPExcel_Shared_String::StrToTitle($mixedCaseString);
 	}	//	function PROPERCASE()
 
 
diff --git a/Classes/PHPExcel/Shared/String.php b/Classes/PHPExcel/Shared/String.php
index 5f59685..3b88ec9 100644
--- a/Classes/PHPExcel/Shared/String.php
+++ b/Classes/PHPExcel/Shared/String.php
@@ -583,6 +583,48 @@ class PHPExcel_Shared_String
 		return substr($pValue, $pStart, $pLength);
 	}
 
+	/**
+	 * Convert a UTF-8 encoded string to upper case
+	 *
+	 * @param string $pValue UTF-8 encoded string
+	 * @return string
+	 */
+	public static function StrToUpper($pValue = '')
+	{
+		if (function_exists('mb_convert_case')) {
+			return mb_convert_case($pValue, MB_CASE_UPPER, "UTF-8");
+		}
+		return strtoupper($pValue);
+	}
+
+	/**
+	 * Convert a UTF-8 encoded string to lower case
+	 *
+	 * @param string $pValue UTF-8 encoded string
+	 * @return string
+	 */
+	public static function StrToLower($pValue = '')
+	{
+		if (function_exists('mb_convert_case')) {
+			return mb_convert_case($pValue, MB_CASE_LOWER, "UTF-8");
+		}
+		return strtolower($pValue);
+	}
+
+	/**
+	 * Convert a UTF-8 encoded string to title/proper case
+	 *    (uppercase every first character in each word, lower case all other characters)
+	 *
+	 * @param string $pValue UTF-8 encoded string
+	 * @return string
+	 */
+	public static function StrToTitle($pValue = '')
+	{
+		if (function_exists('mb_convert_case')) {
+			return mb_convert_case($pValue, MB_CASE_LOWER, "UTF-8");
+		}
+		return ucwords($pValue);
+	}
 
 	/**
 	 * Identify whether a string contains a fractional numeric value,
diff --git a/Classes/PHPExcel/Writer/Abstract.php b/Classes/PHPExcel/Writer/Abstract.php
index 3901e76..2ac779c 100644
--- a/Classes/PHPExcel/Writer/Abstract.php
+++ b/Classes/PHPExcel/Writer/Abstract.php
@@ -45,6 +45,8 @@ abstract class PHPExcel_Writer_Abstract implements PHPExcel_Writer_IWriter
 
 	/**
 	 * Pre-calculate formulas
+	 * Forces PHPExcel to recalculate all formulae in a workbook when saving, so that the pre-calculated values are
+	 *    immediately available to MS Excel or other office spreadsheet viewer when opening the file
 	 *
 	 * @var boolean
 	 */
@@ -89,7 +91,12 @@ abstract class PHPExcel_Writer_Abstract implements PHPExcel_Writer_IWriter
 	}
 
     /**
-     * Get Pre-Calculate Formulas
+     * Get Pre-Calculate Formulas flag
+	 *     If this is true (the default), then the writer will recalculate all formulae in a workbook when saving,
+	 *        so that the pre-calculated values are immediately available to MS Excel or other office spreadsheet
+	 *        viewer when opening the file
+	 *     If false, then formulae are not calculated on save. This is faster for saving in PHPExcel, but slower
+	 *        when opening the resulting file in MS Excel, because Excel has to recalculate the formulae itself
      *
      * @return boolean
      */
@@ -99,6 +106,8 @@ abstract class PHPExcel_Writer_Abstract implements PHPExcel_Writer_IWriter
 
     /**
      * Set Pre-Calculate Formulas
+	 *		Set to true (the default) to advise the Writer to calculate all formulae on save
+	 *		Set to false to prevent precalculation of formulae on save.
      *
      * @param boolean $pValue	Pre-Calculate Formulas?
 	 * @return	PHPExcel_Writer_IWriter