How Accurate is the Flightscope Trajectory Optimizer?

I'm curious as to how accurate the Flightscope Trajectory Optimizer is for everyone here. I know my launch numbers, but when I input them it tells me my golf ball should be traveling about 15-20 yards further than it usually does on the "hard" ground setting, it's nearly dead on with the "medium" ground setting, and a little short with the "soft" setting. The disparity between hard and the rest of the settings also seems unusually large to me.

It just seems odd since Colorado is generally regarded as having "hard" ground (especially in winter when greens can bounce like cartpaths), yet the "hard" ground setting appears way off to me.

I've used it from time to time in conjunction with my launch monitor (a GC2). I'll hit shots on the launch monitor then play with the numbers in Flightscope Trajectory Optimiser to see what will happen if I hit the ball a degree or two higher or take off 300rpm of spin, that sort of thing.

I only ever use the carry yardage though and for that it's not hugely different to the flight model used by the GC2. Once the ball hits the ground there's a fair amount of guess work going on in the Optimiser so I just ignore roll numbers. I get a fair idea about what the ball does on the green from the pitch mark compared to the ball's resting position and know my total yardages on the course by using GPS. There's so much variation in roll when the ball hits the deck I would be tempted to ignore this totally on the Optimiser.