We report simultaneous measurements of the concentration profile and the free energy of the submerged PS blocks of PDMS-PS diblock copolymers spread as monolayers at the air surface of ethyl benzoate as a function of surface concentration. A parabolic concentration profile is found to give the best fit to neutron reflectivity curves among the set of two-parameter models examined. The maximum extension h*/Rf is comparable to previously reported values obtained from a variety of techniques for similar values of the reduced surface density a* and indicates some stretching perpendicular to the surface. As * increases from 1.3 to 4.2, the energy per PS block (obtained from surface tension measurements) increases sharply while the dependence of h* on a* is much weaker than the Vs power law dependence predicted for the strongly stretched regime. Thus, the energy required to stretch the chains for this system appears to be much larger than predicted by current theories.