Is itinerary is must to apply for a chinese visa under Express service

Hi, I am working for a china based company for last two years in India as an independent consultant. I am planing to take a customer to our HQ in china for a factory visit.
To day I went to my application agent in Chennai to apply to go to China. He was asking me to submit the Itinerary along with the application.
As I am not sure on exact date, I have not booked ticket.
Kindly advice if the itinerary is mandatory to process my application