Autos flower when they become sexually mature, which is generally 4 to 7 weeks from seed. The flowering times cited are just that - flowering times. The clock on the 8 to 10 week flowering time begins when the plant starts flowering.
The “reduced sunlight” triggering of cannabis is irrelevant for autos. It refers to photoperiod plants only.
Somebody messed up and put photoperiod information on the autoflower page. I find lots of mistakes in general information on cannabis websites. Midwest has you covered. The auto will finish on its internal timer and not the calendar.