Andhra Pradesh State Road Transport Corporation [Apsrtc] — Delay in departure

Address:

600107

I travelled on 21.05.2016 from chennai to tirupati through apsrtc bus service no. 6244 (Chi-rct), actual departure time is 20.30 from cmbt bus stand bus started at 20..40 from bus stand and again at exit driver (T. Raja reddy, contact no. [protected]) stopped bus for more than a half an hour for loading luggages on to bus for which driver was charging money also. Is it a correct way to get luggage onto board and keeping on wait the passengers for such a long time.
I booked this particular bus which departs at 20.30 so that i will reach my destination soon by 23.45. Due to the delay by the driver he started from cmbt at 21.20 and reached tirupati by 00.45.