"I think your whole trouble is that you don't beleive there is a mid point ( split weight. That at the full extent of the stride you are on the heel of the front foot and the toe of the back foot. "
Usually their is ISN'T any such situation. Sure, you see both feet on the floor, but you can easily tell that only one of them has weight at a time. Usually you'd be hard pressed to find even a single frame in a video where you could even make an argument that the weight might be divided.
Those who maintain the false belief that the weight is divided in actual dancing can be readily observed to be failing to commit their body to the movement - they hold it stationary while reaching their moving foot out, which is just all wrong in any dance but tango (and even there, it should only happen to a limited degree at the start of an action)
"If you are one of those who turns into a step and not at the end"
If you had a mature understanding of the concepct of "turn" in ballroom dancing, you would understand that some parts of the turn occur BEFORE the first step, and others occur only upon arrival on the second - but very little occurs in between.
Remeber, you have many SEPERATE variables: Body alignment, foot alignment, direction of movement across the floor - each has times during the overall "turn" when it is changing, and times when it is not changing, despite one of the other variables being in the process of change.