Dispute it out of principle if nothing else. Speaking from recent experience, you will get the runaround and it may take up to a year to get your hearing. The judge will most likely not give you the chance to state your argument (that would require admitting there was a mistake) but they will knock the price down. It may not seem worth the trouble, but they are on a rampage with the bullshit parking tickets. Just paying the ticket without disputing it is letting them get away with it.