Moding 9 kHz to 10 kHz Channel step

I have a Kenwood KT-6040 from Europe that I brought over to the US and use a step down transformer to play. According to the service manual this tuner board and micro chip has the ability to be set up to switch to the US 10 kHz AM channel steps versus the European 9 kHz steps. Do any of you know about or know of someone who could give any advice on this mod?