H1B and L1B total duration of stay

Dear Friends,

I came to US on L1 visa on April 2005 and stayed till Oct 2005 in xx1 L1B petition

again I came on L1B petirion xx2 on July 2006 and returned on Nov 2006 and after that I did not come to US for 1 year 9 months.

In Aug 2008 I came on L1B visa on petition xx2 and in jan 2012 i got H1B approved with change of status and till date working on H1B…

My question is my 6 year starts from April 2005 or it starts from Aug 2008 (As I was 1 year 9 months outside US)

Please let me know on this. Thanks for all your help