Negative.
It does not matter how far out from the hub the magnet is placed because the magnet will only pass by the sensor once a rotation.

S=D/T
You program the computer with the circumference of the wheel and the sensor counts each time the magnet passes it by.
The inter part of the wheel and the outer part take the same amount of time to make one rotation. The edge of a wheel moves at a faster rate than the inner part because it is moving a greater distance but they take the same amount of time to complete one rotation.
The bike moves forward the same distance as the circumference as the wheel each rotation.
So what your computer is calculating is: speed equals the circumference of the wheel (the distance the bike moves each rotation of the wheel) divided by the time it takes the wheel to complete one rotation.