[Alan Anderson]

Using 1x decoding on a quadrature input, the values go 0, 1, 2, 3, 4...

Using 4x decoding, the values change four times as often but by one fourth the amount: 0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50...

You get the same value for the same amount of rotation, just with a different precision.