If you drop your timer by an hour every week, you'll notice almost all cultivars start flowering at about 14/10Yep
Yep,,Mother nature can does the same thing at 13/11.
We indoor people just use 12/12 as a generalized thing because it cuts on electric use, costs a few dollars less, and does the same thing 14/10 would do.
I had a plant go into flower at 15/9 and by the time i figured out why, it was revegging lol.