That's the whole issue,servicing. Holden should not of stretched them out. Given the higher capacity sump it just did not work.
15,000 kilometre interval turns into 20,000! Ever seen inside one after 200+? I don't know how the oil flows then when the sludge falls off, pick up blocks then game over seen it happen.

Some people are buying new engines from holden, a lot are needing timing chains replaced along with tensioners but lots of workshops won't touch inside them incase they dislodge some crud!