Would This Count As A Fatal Error ?

Ive been fighting a speeding ticket for a year now . I got x copper to represent me and they lost the case. I re-opened the case and went for early resolution, talked to prosecutor and she said the cop reduced ticked on the side of the high way she isn't willing to do anything and if i go to trial shell go for the full speed . I was clocked doing 131 in a 100 cop reduced it to 120 in a 100 . I got the disclosure and went home , my wife was looking over the ticket and noticed that the cop put I was doing 100 kmh in a poster 100 zone . Is this considered a fatal error ? The cops notes do say he clocked me doing 131 so I ask do i have a chance winning with that on the ticket or will the court amend the speed and use the 131 in his notes .

Also i have heard from a friend that works ad a court house that if the cop noticed the error before he filed the ticket he can amend the speed and then file the ticket with the proper speed , is this true ?