Just a thought... If we consider the amount of momentum present in these turns we will see momentum will determine what happens first.
From a dead stop, with our skis across the hill and our bodies in a good countered traverse position, we can simply move the hips in line with our feet and head to release the edges allowing the tips to seek the fall line and the edge change does not occur until close to the fall line.
Conversely, with ample forward momentum our ski tips will stay put as our mass moves toward the apex first and the edge change occurs before or probably more accurately with the new turn beginning.
In between these two extremes is a spectrum where the edge change will occur depending on how much forward momentum we have. Momentum is the key here! To the blending point, the amount of forward momentum will determine how much pivot vs. tipping is needed at the top of the turn!