diff --git a/lib.php b/lib.php
index 8daf024..cda89ba 100644
--- a/lib.php
+++ b/lib.php
@@ -14,8 +14,10 @@ function attforblock_supports($feature) {
         case FEATURE_GRADE_HAS_GRADE:   return true;
         case FEATURE_GROUPS:            return true;
         // Artem Andreev: AFAIK it's not tested
+        // we need implement filtration of groups list by grouping
         case FEATURE_GROUPINGS:         return false;
         // Artem Andreev: AFAIK it's not tested
+        // harder "All courses" report
         case FEATURE_GROUPMEMBERSONLY:  return false;
         case FEATURE_MOD_INTRO:         return false;
         case FEATURE_BACKUP_MOODLE2:    return true;
@@ -45,7 +47,7 @@ function attforblock_add_instance($attforblock) {
         $DB->insert_record('attendance_statuses', $rec);
     }
 						
-//    attforblock_grade_item_update($attforblock);
+    attforblock_grade_item_update($attforblock);
 //	attforblock_update_grades($attforblock);
     return $attforblock->id;
 }
@@ -217,10 +219,10 @@ function attforblock_cron () {
  * @param int $userid optional user id, 0 means all users
  * @return array array of grades, false if none
  */
-function attforblock_get_user_grades($attforblock, $userid=0) {
+/*function attforblock_get_user_grades($attforblock, $userid=0) {
     global $CFG, $DB;
     
-	require_once('locallib.php');
+	require_once('_locallib.php');
 	
     if (! $course = $DB->get_record('course', array('id'=> $attforblock->course))) {
         error("Course is misconfigured");
@@ -242,7 +244,7 @@ function attforblock_get_user_grades($attforblock, $userid=0) {
     }
 
     return $result;
-}
+}*/
 
 /**
  * Update grades by firing grade_updated event
@@ -250,7 +252,7 @@ function attforblock_get_user_grades($attforblock, $userid=0) {
  * @param object $attforblock null means all attforblocks
  * @param int $userid specific user only, 0 mean all
  */
-function attforblock_update_grades($attforblock=null, $userid=0, $nullifnone=true) {
+/*function attforblock_update_grades($attforblock=null, $userid=0, $nullifnone=true) {
     global $CFG, $DB;
     if (!function_exists('grade_update')) { //workaround for buggy PHP versions
         require_once($CFG->libdir.'/gradelib.php');
@@ -283,7 +285,7 @@ function attforblock_update_grades($attforblock=null, $userid=0, $nullifnone=tru
             $rs->close($rs);
         }
     }
-}
+}*/
 
 /**
  * Create grade item for given attforblock
@@ -321,7 +323,6 @@ function attforblock_grade_item_update($attforblock, $grades=NULL) {
         $params['gradetype'] = GRADE_TYPE_VALUE;
         $params['grademax']  = $attforblock->grade;
         $params['grademin']  = 0;
-
     } 
     else if ($attforblock->grade < 0) {
         $params['gradetype'] = GRADE_TYPE_SCALE;
diff --git a/locallib.php b/locallib.php
index ed99fb3..2f5721b 100644
--- a/locallib.php
+++ b/locallib.php
@@ -332,8 +332,9 @@ class attforblock {
     private $sessioninfo;
 
     private $statuses;
-    private $usertakensesscount;
-    private $userstatusesstat;
+    // arrays by userid
+    private $usertakensesscount = array();
+    private $userstatusesstat = array();
 
     /**
      * Initializes the attendance API instance using the data from DB
@@ -700,7 +701,7 @@ class attforblock {
         $sesslog = array();
         $formdata = (array)$formdata;
 		foreach($formdata as $key => $value) {
-			if(substr($key, 0, 4) == 'user' && $value !== '') {
+			if(substr($key, 0, 4) == 'user') {
 				$sid = substr($key, 4);
 				$sesslog[$sid] = new Object();
 				$sesslog[$sid]->studentid = $sid;
@@ -715,12 +716,14 @@ class attforblock {
 
         $dbsesslog = $this->get_session_log($this->pageparams->sessionid);
         foreach ($sesslog as $log) {
-            if (array_key_exists($log->studentid, $dbsesslog)) {
-                $log->id = $dbsesslog[$log->studentid]->id;
-                $DB->update_record('attendance_log', $log);
+            if ($log->statusid) {
+                if (array_key_exists($log->studentid, $dbsesslog)) {
+                    $log->id = $dbsesslog[$log->studentid]->id;
+                    $DB->update_record('attendance_log', $log);
+                }
+                else
+                    $DB->insert_record('attendance_log', $log, false);
             }
-            else
-                $DB->insert_record('attendance_log', $log, false);
         }
 
         $rec = new object();
@@ -729,7 +732,7 @@ class attforblock {
         $rec->lasttakenby = $USER->id;
         $DB->update_record('attendance_sessions', $rec);
 
-        // TODO: update_grades
+        $this->update_users_grade(array_keys($sesslog));
         // TODO: log
         redirect($this->url_manage(), get_string('attendancesuccess','attforblock'));
     }
@@ -838,16 +841,16 @@ class attforblock {
     public function get_user_taken_sessions_count($userid) {
         global $DB;
 
-        if (!isset($this->usertakensesscount))
-            $this->usertakensesscount = get_user_taken_sessions_count($this->id, $this->course->startdate, $userid);
+        if (!array_key_exists($userid, $this->usertakensesscount))
+            $this->usertakensesscount[$userid] = get_user_taken_sessions_count($this->id, $this->course->startdate, $userid);
 
-        return $this->usertakensesscount;
+        return $this->usertakensesscount[$userid];
     }
 
     public function get_user_statuses_stat($userid) {
         global $DB;
 
-        if (!isset($this->userstatusesstat)) {
+        if (!array_key_exists($userid, $this->userstatusesstat)) {
             $qry = "SELECT al.statusid, count(al.statusid) AS stcnt
                       FROM {attendance_log} al
                       JOIN {attendance_sessions} ats
@@ -861,10 +864,10 @@ class attforblock {
                     'cstartdate'    => $this->course->startdate,
                     'uid'           => $userid);
 
-            $this->userstatusesstat = $DB->get_records_sql($qry, $params);
+            $this->userstatusesstat[$userid] = $DB->get_records_sql($qry, $params);
         }
         
-        return $this->userstatusesstat;
+        return $this->userstatusesstat[$userid];
     }
 
     public function get_user_grade($userid) {
@@ -876,10 +879,24 @@ class attforblock {
     // In the future we can implement another methods:
     // * all sessions between user start enrolment date and now;
     // * all sessions between user start and end enrolment date.
+    // While implementing those methods we need recalculate grades of all users
+    // on session adding
     public function get_user_max_grade($userid) {
         return get_user_max_grade($this->get_user_taken_sessions_count($userid), $this->get_statuses());
     }
 
+    public function update_users_grade($userids) {
+        $grades = array();
+
+        foreach ($userids as $userid) {
+            $grades[$userid]->userid = $userid;
+            $grades[$userid]->rawgrade = $this->get_user_grade($userid) / $this->get_user_max_grade($userid) * 100;
+        }
+
+        return grade_update('mod/attforblock', $this->course->id, 'mod', 'attforblock',
+                            $this->id, 0, $grades);
+    }
+
     public function get_user_filtered_sessions_log($userid) {
         global $DB;
 
@@ -996,4 +1013,23 @@ function get_user_courses_attendances($userid) {
     return $DB->get_records_sql($sql, $params);
 }
 
+function update_all_users_grades($attid, $course, $context) {
+    global $COURSE;
+
+    $grades = array();
+
+    $userids = get_enrolled_users($context, 'mod/attforblock:canbelisted', 0, 'u.id');
+
+    $statuses = get_statuses($attid);
+    foreach ($userids as $userid) {
+        $grades[$userid]->userid = $userid;
+        $userstatusesstat = get_user_statuses_stat($attid, $course->startdate, $userid);
+        $usertakensesscount = get_user_taken_sessions_count($attid, $course->startdate, $userid);
+        $grades[$userid]->rawgrade = get_user_grade($userstatusesstat, $statuses) / get_user_max_grade($usertakensesscount, $statuses) * 100;
+    }
+
+    return grade_update('mod/attforblock', $course->id, 'mod', 'attforblock',
+                        $attid, 0, $grades);
+}
+
 ?>