Ive seen years ago a NZ GRB that had done around 50k that started burning oil like it was fuel, it had been poorly maintained and has carbon build up in the ring grooves leading to poor oil control. this is a major problem seen in late model Japanese imports with poor service history, once the carbon is there its impossible to remove without pulling the engine down, I carried out this job on a 2006 audi a6 late last year, less than 100k on the clock but the engine was a black carbon pit.