@chronicals77 It differs by plant health and environment, but plants begin to flower on day one of flip. Yellowing around bud sites occurs on day one. The plant is drawing nutrients from around the bud sites to initiate flower growth. 5-7 days in you should have flowers already developed. Anyone not counting the first day of flip in flower is doing it wrong.
If I don't count that first week, then my OG's, GSC's, GG4, "Mystery", Animal Crosses, and every other strain I've ever grown (except something called "Unicorn Crusher" and a Jack cross that each looked could go another week or two) are all "7-8 week" plants (again, that is minus the first week), and I had a Blue Dream that was just over 6 weeks (if that first week doesn't "count"). Nope, that isn't the case. I run 8-9 week plants. Flowering begins day 1, by day 7 there are flowers. Flowering does not "initiate" when there is already a flower present.
I think the "argument" stems from the difference in environment and overall plant health. Ideal environment and optimal plant health will shorten bloom. Extreme example; a plant that will take 56 days, flip to finish (let's say 80/20 milky/amber), while that exact same plant ("sister" clone) will take significantly longer outdoors. Yes, this is the difference between "out" and "in", but there is also a difference in the "sophistication" between individual indoor grows. One may take only 8-9 weeks with a particular strain, while another takes 11-12 to achieve the same level of maturation.
"Stretch" is a part of the flowering phase. The amount of stretch and it's duration is strain/environment dependent. Typically occurs during the first 3 weeks. There are methods to mitigate this.
