  Experimental data for integrated kaon multiplicities taken at HERMES and
COMPASS measurements look incompatible with each other. In this talk, we
investigate the effects of hadron masses calculated at leading-order and
leading twist at the kinematics of these two experiments. We present evidence
that Hadron Mass Corrections can fully reconcile the data for the $K^+/K^-$
multiplicity ratio, and can also sizeably reduce the apparent large discrepancy
in the case of $K^+ + K^-$ data. Residual differences in the shape of the
latter one remains to be understood.
