  Critical discussion of the recently published results [Muller, A. and
Aschenbach, B. 2007 Class. Quantum Grav. 24, p. 2637; arXiv:0704.3963] on the
non-monotonic orbital velocity profiles of the Keplerian motion of test
particles and l = const motion of test perfect fluid around K(a)dS black holes
is given, and the discrepancies concerned the existence of the non-monotonicity
in dependence of the spacetime parameters are corrected. Moreover a new
non-monotonic behaviour of the Keplerian orbital velocity in the Kerr-antide
Sitter spacetimes is highlighted.
