A833 input shaft Q's

I bought a used input shaft off ebay for my spare A833. I need to replace the input shaft on the spare because someone accidentally snapped of the first two inches of the shaft where it goes in the pilot hole when removing it from their car.

The ebay seller sent me two input shaft saying that the one I bought may be too short. It looks like it was cut down 1 inch. The other input shaft is of normal length. I don't know why he just didn't send me the good one in the first place. They are both 24 tooth.

My question is, I have read of people cutting down the input shaft for a reason but I can't recall why. Does anyone know?