It's given that i have to score 156 points to get the PGDM, what if i fall short by a whisker? Are there students who fail to clear it?

You will be selected in TSM not only by the MAT score. There will be a GD and a PI. Those scores will also be taken into consideration too. So, if u got less than 156 points, apply for admission and do the GD and PI well. If your overall performance is good, you will surely be got selected. All the