Wondering why the service interval for the Solterra in Australia is 12 months/15000 km (9321 miles), while in the US it's 6 months/5000 miles. I'm guessing the excuse might be weather/road conditions,? (I'm in the US but have a similar climate to Sydney Australia.) If I go Ausie-style, I could do wheel-bolt/fluids etc checks myself in between the longer Ausie intervals. Any thoughts?