The total final supply of DAO tokens is not fixed. Despite the fact that the planned total final supply of DAO Token is of 312M of tokens, this will change to the Toll Bridge mechanism: if a DAO investor, that participated in private sale, wants to claim his tokens in advance, without waiting the regular distribution, he can do paying a toll. The toll value changes over time, and the subtracted tokens are burned reducing the final token supply. 

For further information about DAO token please check the DAO Economics Paper.