"professional extenders" are often "profit extenders", as the supervising physician can enable his / her practice to see more volume and better match revenues and costs (ie have lower cost labor do lower revenue / acuity work). the "savings" from this often end up accruing to the owner of the practice. increasingly this owner is a large hospital system, but they take this delegation a step further, using lower cost primary care as a way to increase volume to higher acuity / reimbursed hospital procedures.