  Whereas a nonrelativistic distorted wave model fails to quantitatively
describe analyzing power data for exclusive proton-induced proton-knockout from
the 3s_{1/2} state in Pb-208 at 202 MeV, the corresponding relativistic
prediction provides a perfect description, thus suggesting that the Dirac
equation is the more appropriate underlying dynamical equation. We check the
consistency of this rsult by comparing predictions for both dynamical models to
new high resolution data for 3s_{1/2} knockout in Pb-208 at a higher incident
energy of 392 MeV.
