Calender deviation

Hello Everyone,
 I am facing a problem in Hijri Calender there is a Deviation with 11 days !

I have read the solution.

But I am not getting how we should implement this.
how can I add 11 days in the calendar,
and how   <"Sep-29-2000 ad">:11 will subtract 2 days

Edit lxecal.nlt 
 DEFINE calendar

         calendar_name              =       "Arabic Hijrah"

           DEFINE calendar_deviation
            deviation_data           = {
                                        <"Sep-29-2000 ad">:1
                                        }
           ENDDEFINE calendar_deviation

        ENDDEFINE calendar


Please is there anyone who can help me in solving the 11 days deviation.
Please respond as soon as possible this is urgent!

Thank you