my mate manages a motor fsctors, and he says when the oil reps come around even they say oils do not las the manufacturers times.
For instance, peugeot say 20k for an oil service on the 206 Gti or 2yrs. No way will it last that long, and thats on standard oil.
Plus considering how hard i push my car i think the gearbox deserves to be treated, so once i move away from dealer servicing after warranty i will get someone to do it for me, ( or may do it myself if its not too cold)