Ontario Highway Traffic Act

I was pulled over for passing an officer on an off ramp on a 400-series highway. The officer used the yellow warning sign with a speed posted on it (sign says 70km/h) to charge me. The officer claims I was going 92km/h and gave me a ticket for 85 in a 70. I tried to explain to the officer that the posted speed limit is 100km/h at that they yellow ...