I had a long conversation with Cain about the best pads/ shoes for my 2009 4/4 (Caparo) and he said that for a road car, by far the best was Pagid. I can confirm they have excellent all round performance and are less sensitive to temperature, good when cold and they don't fade when worked hard, when others would.
Unless there is something badly wrong with one of the calipers, a 30% discrepancy seems unlikely to me.
Occam's razor says it will pads and/or hydraulics.
