The top level numbers are the area size in YxY pixels it uses to grab the sample.

The lower level numbers are the modifier key area size

This script opens up a palette with radio controls, use it to set the eyedropper sampler size text pref on the fly.

If you are doing retouching on large size images sometimes the defaults of 1 and 5 are a bit tiny.
This way you can toggle the scale to match the image you are working on without having to restart AE.