Flower time related to height

I am curious if increased flowering times in the Grobo are related to shorter plants being further from the light.

Not sure I understand the question but 95% of upward growth takes place during Veg and the Transition Stretch. Once in flower expect some upward growth but not much.

If you extend flower it is to time the trichomes so they are cloudy and amber mixed when harvesting, nothing to do with height.