Questions With Growing Times

I just finished my first grow with 1x Jack Herer, 2x White Widow and 1x Lemon OG. Here's the thing I waited the usual 8 weeks into flowering before starting to harvest and once I started drying and curing I noticed all of my buds getting a brown tint to them. I realized that this was because all of the trichromes had turned amber on the buds. I obviously harvested too late. I harvested the Lemon OG the 7th week when I noticed the trichromes turning amber. Since I was growing different strains that would rule out the problem being with a specific strain. I know that harvesting times vary for different strains etc but everything I have read said 8 weeks flowering time (once you switch to 12/12 light cycle) minimum for Sativa strains. So what's the deal?

You can just get one of those microscopes that you can look at the resin glandes with. Will take all guessing out of it

Plus remember that breeders tell you 8 weeks but in reality it's usually around 10 weeks. They don't tell you there is a transition time right at first flowering of about 2 weeks

Yeah I have one of those magnifying lenses to check but since I was in the 7th week I didn't really think to check the buds yet. If it was really 10 weeks then I would have harvested too early and not too late. correct?