The stretch you want to create wants to pull the rear shoulder down. resist with some front side scrunch, which is shoulder down and in.
hmm maybe level isnt the right word. I want her to stop lifting her front shoulder up when she plants. it is better here than it was before, her instructor has her doing drills going from toe touch to heel plant and driving front shoulder down. In fact when she stops and heal plant and holds it it's close to the image above, but when she goes full speed she still lifts the shoulder.