Again, I am not questioning "Why Chorus" there. It is just that I would have preferred instrumental pieces there. Clearly, in most cases, we agree that there is a "soundtrack" reason for having the chorus - but the question is is there a musical reason as well? Only Raja can answer that.
Also, rprasad's perspective on spontaneity is also interesting and plausible.
rprasad, your views on 'professionalism' are spot on - a fitting answer to over-zealous professional types(so professional that they are in the hub during office time) questioning his ethics that he takes money and produces sub-par stuff. This is a creative art, and a lot of factors determine the output - no way you can say that he deliberately underperforms. The fact that many duds got great music is proof that output is not related to great story/scenario/director alone - it is a random function of various factors hence we cant really comment much on professionalism here.