I would so contest that ticket. From your description of events he is either giving you a reasonable chance to win or he wont even show. Obviously if he doesn't show, you automatically win. If he does show he basically gave you the ammunition to fight and win in court (being, the things he said and what he actually wrote on the ticket).
If you want to be more knowledgeable about how to handle these situations, get this book
"How to Fight Your Ticket in California" by
Nolo Press.It is a simple read, and you only need to read the sections that are applicable to your circumstances. I have used that book on several occasions. In ten years I have been pulled over 16 times. I contested all 16 and only had to paid up once.
That one time was in Orange County and I lost because the Law and the principles of Physics in general work differently in the OC. ( What does one expect from the largest county in US history to ever file for bankruptcy) I guess the really need the money....
Good Luck my friend...