Wrong dates statistics per month

function _jsDate($group,&$element, $widget=null, $diff=null){
	if(!isset($element->timestamp)){
		switch($group){
			case '%H %j %Y'://day
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime($parts[2], 0, 0, 1, $parts[1], $parts[0]) - $this->timeoffset;
				break;
			case '%j %Y'://day
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, 1, $parts[1], $parts[0])- $this->timeoffset;
				break;
			case '%u %Y'://week
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, 1, $parts[1]*7, $parts[0])- $this->timeoffset;
				break;
			case '%m %Y'://month
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, $parts[1], 1, $parts[0])- $this->timeoffset;
				break;
			case '%Y'://year
				$element->timestamp = gmmktime(0, 0, 0, 1, 1, $element->calculated_date)- $this->timeoffset;
				break;
		}
	}

	if(isset($widget->widget_params->period_compare)){
		if($widget->widget_params->period_compare=='last_period' && isset($widget->elements)){
				$element->timestamp=$element->timestamp+$diff;
		}
	}

	$element->year = date('Y',$element->timestamp);
	$element->month = date('m',$element->timestamp)-1;
	$element->day = date('j',$element->timestamp);
	if($widget->widget_params->date_group=="%H %j %Y"){
		$element->hour = date('G',$element->timestamp);
	}
}

function _jsDate($group,&$element, $widget=null, $diff=null){
	if(!isset($element->timestamp)){
		switch($group){
			case '%H %j %Y'://day
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime($parts[2], 0, 0, 1, $parts[1], $parts[0]);
				break;
			case '%j %Y'://day
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, 1, $parts[1], $parts[0]);
				break;
			case '%u %Y'://week
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, 1, $parts[1]*7, $parts[0]);
				break;
			case '%m %Y'://month
				$parts = explode(' ',$element->calculated_date);
				$element->timestamp = gmmktime(0, 0, 0, $parts[1], 1, $parts[0]);
				break;
			case '%Y'://year
				$element->timestamp = gmmktime(0, 0, 0, 1, 1, $element->calculated_date);
				break;
		}
	}

	if(isset($widget->widget_params->period_compare)){
		if($widget->widget_params->period_compare=='last_period' && isset($widget->elements)){
				$element->timestamp=$element->timestamp+$diff;
		}
	}

	// Setting the timezone
	$joomlaConfig = JFactory::getConfig();
	if(!HIKASHOP_J30)
		$offset = $joomlaConfig->getValue('config.offset');
	else
		$offset = $joomlaConfig->get('offset');		

	date_default_timezone_set(JFactory::getUser()->getParam('timezone', $offset));

	$element->year = date('Y',$element->timestamp);
	$element->month = date('m',$element->timestamp)-1;
	$element->day = date('j',$element->timestamp);
	if($widget->widget_params->date_group=="%H %j %Y"){
		$element->hour = date('G',$element->timestamp);
	}
}