93 ft for 60-0mph braking means that it pulled an average of about 1.3g.

If the speed measurement for 60mph was high by just 4mph, the force of braking was really 1.1g which would imply a real 60-0 braking distance of about 109ft.

As you can see, accuracy in the speed measurement is very important. The equation describing this is (remember to use consistent units):

x = v^2 / (2 * a)

where x is the braking distance, v is the starting velocity and a is the deceleration. Since the original velocity is squared, the accuracy of the measurement of the velocity is very important. As the tester said, they are still nailing down the initial velocity measurements so it is probably best not to make much of the results until the error on that measurement is very small.

The moral of the story is: Whenever someone quotes you a number you should ask what the error on that number is. If they can't answer this question well, their number is somewhat meaningless. Nothing is ever perfectly measured...so knowing the error on a number is key in understanding the number.