I remember Mini changed their OCI from 15k to 10k at some point. I remember thinking it was crazy that a family members Mini Cooper S had 15k intervals. The OLM didn't seem to care the thing was run hard either, I think it was only based on mileage (my 08 Honda seemed to have a much better OLM). Plenty of stories of sludged up MINI engines if I remember correctly. So maybe Mazda noticed something?
http://www.motoringfile.com/2012/04/16/mini-shortens-oil-change-interval/
http://www.motoringfile.com/2012/04/16/mini-shortens-oil-change-interval/