Shaken

Yesterday I got my car back from having to 'shaken'. Shaken is the mandatory evaluation which every car must pass through every 2 years or so. Needed to replace the electronic harness in the steering wheel, but it seems everything else checked out ok. What I don't understand is why my shaken was only renewed for just one year and not two? Perhaps it has to do with my mileage which is over 120000k. I've put over 25000k on the car since I bought it last summer.