Punching on gas with often take it more than 10mph in just a moment’s time. Learned that the hard way myself. I saw a police with a speed gun up ahead, got startled, and punched on the gas. There was a van next to me, I was about to try to move away from, so it was gas rather than brakes, that i punched.
After much research, their laser is accurate. With radar they can confuse it with another car, but there’s little that can go wrong with the laser guns (beyond non-calibration and stuff attorney’s tend to look at.) So it’s likely you did hit the speed they said. Which is over 90mph.
They can clock for quite a distance, without being visible to oncoming cars. They could easily see 8mph over the limit, and track it waiting to see if you were going in a range that included speeding up over the classic 10mph wiggle room they tend to give. A punch out to higher would do it.
I don’t mean to be disappointing here, but… that you “pulled over and waited for him”, tells me, there’s something different or more to this story than you’ve told.