I'll concur with all above, I've had autos that only ambered after a 45-60 day cure in the jar. With autos, the flowers are ripe many weeks before a photo plant. For example, you would have another 40 days if you were growing a photoperiod WW from seed; in this sense, the chemicals in the trichomes are not always at the point of maturing to an amber color. The plant is ready to come down, but they just haven't changed colors. I think it has a lot to do with when the flowering actually starts, really really early strains (regardless of how long they take to finish) usually don't amber on me. Strains that flower after a longer vegetative state, then finish quickly, almost always amber for me, and do so very rapidly.