Relative doubly differential cross sections for the Penning ionization of Ar by spin-state-selected metastable He (1s2s) are reported at four center-of-mass collision energies covering the range E=1.8-6.3 kcal/mol in a crossed supersonic beam experiment employing a rotatable mass spectrometer detector. The measurements are sufficiently dense in velocity space as to avoid having to functionalize the differential cross sections in order to transform the intensities into the c.m. The Ar+ product is scattered sharply forward with respect to the incident direction of Ar at all energies for both spin states, increasingly so at higher E, but with a persistent backward-hemisphere component. On the average the products have lost energy upon recoil, mean recoil energy (E’) < E, except for S-1 at high E, but E’ is found to depend strongly on c.m. recoil angle theta, with forward scattering yielding (E’(theta)) approximate to E and sideways up to 50% energy loss. Extensive comparison is made with predictions based on previously determined He*+Ar optical potentials and spectroscopic ion exit channel potentials. Agreement is generally good for both spin states, except for a significant discrepancy in backscattered intensity for S-1 that grows from a factor of 2-6 from lowest to highest E, theory falling below experiment. An alteration to the repulsive part of the S-1 potential suggested by previous work fails to improve the comparison, but does show that the angle-energy coupling is uniquely sensitive to the form of the repulsion. The results appear to indicate nonexponential behavior of the discrete-continuum coupling (imaginary part of the optical potential) at short range.