I tasted a few of the cookies just before bedtime…along with some milk. And it was a good thing. After baking them at 10-15 minutes (instead of 6-8) they were way too dry and crumbly. Not a good cookie.
Go with the cook’s original time limit. They’ll look like they’re not done yet or only part of them will brown. The closer you get to the entire cookie lightly browning the closer you get to needing some duct tape and a Swiss Army knife to fix them like MacGyver would.
I changed the original post so the times are now correct.
WWMD:–I also stored them in a plastic container with a piece of bread for freshness. As with all baking a cheap oven thermometer attached to one of the grates is a helpful way to make sure your oven is baking at the proper temp. The industry lets the makers be off by between 25 and 75 some degrees. I also let the oven warm up an extra 15-20 minutes after the pre-heat cycle finished.