Ok, I think you're probably right.
Just to clarify, the exercise you recommend for the eccentrics: is it a full squat or seated calf raises?
My hammy flexibility is ok. I can get to almost right angles if I set my back and lean my torso forward, or I can get my palms onto the ground if I round my back. I can't kick myself in the face like my gf however, so I wouldn't say great.