There is of course no single correct answer. Dancing is not an exact science, so it's not about absolute truth but about teacher constantly correcting their students. So even from the same teacher you can hear totally opposite descriptions, depending what they want to correct
In my case, my connection was generally higher in the past than now. Recent teachers tried to make us aware of different roles of lower and upper body, introduced terms like upper center and lower center etc. Lower body is the motor of the couple so you need to feel connection there. Big part of leading happen in hip / thigh area, like opening the partner to PP, closing her etc ... Upper part is for the shape and can have quite different role. However, you need to feel the strong right side of the partner and lady needs to make a shape with upper part of the core (not from the waist) to avoid balance problems, so connecting area extends upwards to the ribs - unless of course in poses when flexibility of the spine (which is varying a lot among ladies) isn't enough to achieve it ... and it can move from right to left in some figures etc ...