No change in number of iteration in FCM() method for clustering

i used following code for fcm but even i change number of iteration i get only 23-25 iteration and no change in OF. Further even if change the "minimum amount of improvement" from 0.1 to 0.001 there is no change in iteration number in result or OF. Suggest any answers

options = [NaN 100 0.001 1];
[centers,U,objFun] = fcm(bupa,2,options);