The 'idiot light' is not based on miles, but on how much oil is actually in the engine. There's a sensor in there that if it touches air, essentially, the light goes on. You can trip this on certain VWs if you turn very sharply & you are low enough on oil.

Compare this to GM/Chevy vehicles where this is a 'solved problem' with their on board DICT computer, it measurements the containment (via resistance? electricity?) in the oil & tells you the 'health' or 'life' of the oil until you need to change it. This leads to a lot more reasonable oil change intervals in line with Mobile's testing over the years: 5k, 7k or 10k change intervals are common.

BMW is one of the few brands that recommends once a season, or 10k, because they know what oil is capable of, in so far as they've removed dip-sticks entirely (retarded decision, but hey). However, most dealerships & shops? They still want that sweet money on that 3k oil change. 5k has become the 'open secret' standard, though.