Incremental Achievements in Google Play Games Unity3d -

i want implement incremental achievement, if score 10 should unlock achievement that. likewise have created achievement scores 40 , 100 etc.

i using method:

 if(score == 10)  {      playgamesplatform.instance.incrementachievement(     "cfjewijawiu_qa", 40, (bool success) => {         // handle success or failure      });  } 

i have written in update() method. same way when score reaches 40. using corresponding achievementid unlock that.

but achievement not getting unlocked. can reason?

thanks in advance.