My question involves a speeding ticket from the State of: Washington

Need to decide to state my perspective in court or accept a "deferral" if no further tickets in 12 mo, violation never on record, but pay $113 fine anyway.

I was last of 3 motorcycles, travelling uphill on clear, dry, low traffic county road. As I came around a bend, saw patrol car off to side of road: I did not know posted limit but glanced at speedometer 40 to 45 ? In mirror, he turned around and pulled behind me with lights: no way...I'm not speeding; pulled to side to let him go by (after 1st bike?)...he rolled window and said to follow; stated 1 guy at 57, 2nd at 46, me at 45 in a 40 MPG, BUT: SINCE FIRST GUY AT 57, I MUST have been going faster and slowed when I saw him...WHICH I DID NOT!! I'm last because I'm going slower. After checking paperwork, he said he was doing us a favor with ticket at 45. I was stunned. BTW: no radar documentation, said he saw it on radar visually.
.....I have completely clean record and ridden over 9yrs no violations...want to keep it that way. So, go to court? take a chance?....or accept the "defferal" in WA if no ticket within 1 yr, it never goes on record...?????