I spoke to 2 agents and they gave me different answers. First agent seemed more informed -

The card dispatched date is your anniv date -mine was Aug 2013

Aug2013-Aug 2014 is my free year
Aug2015-Aug 2015 is my qualification year and I need 40K to re-qualify

Once achieved, the status remains for another year.

Second agent was of the opinion that Aug 2013-Aug 2014 was my qualification year. He also used the card dispatched date as a guideline but said sometimes card is not dispatched for months so it may be inaccurate.

Bottomline - no one knows - and their systems don't tell them expiry dates.