It is shown by calculating the wave transmission coefficient T directly from the WKB absorption coefficient α, for the fundamental ordinary and the second harmonic extraordinary electron cyclotron wave modes propagating perpendicular to the magnetic field in a weakly relativistic magnetoplasma, that the thermal corrections present in α do not affect the functional dependence of T (which in fact, as has been suggested earlier, is also true for non-adiabatic effects like wave reflection, which cannot be treated by a WKB approach). This result can readily be generalized to all harmonic modes except for the fundamental extraordinary wave mode in the so called finite-density regime. For the latter case, general analytical expressions are obtained in the WKB approximation for both α and T.