OK, I'll admit butterflied chicken can be cooked that quickly. But basically all other forms of chicken take longer. For curry for example, even though I cut it into small pieces and it could be cooked only 8 minutes since you're going to cook it in the paste later, it's just not going to brown properly and the flavour is not going to be as good. Normal breasts or thighs take longer as well.
It's been a while since I made a meat-based curry (vegetarian now), but from when I was cooking with meat regularly there were a few things that helped hugely with that - hot pan (common theme, heh), and cooking in batches/not overcrowding the pan. You _definitely_ can't brown chicken for 6 portions of curry in one pan in 6-8 minutes, but you _can_ brown it in 2 (maybe 3) batches in 6 minutes per-batch.
Honestly though, by the time you're accurately gauging browning vs cooking meat, and eyeballing batch size vs pan size, you've moved well past the point of relying on cooking times from recipes.
