  The dependence of the differential cross section
${\mathrm{d}\sigma}/{\mathrm{d}p_{\perp}}$ of inclusive heavy quark production
in pp and $\bar{\mathrm{p}}$p collisions on the renormalization and
factorization scales is investigated. The implications of our results for
experiments at TEVATRON and LHC are discussed. In particular, it is shown that
the NLO QCD predictions for $\bar{t}t$ production at the LHC based on the
Principle of Minimal Sensitivity are by 30-50% higher than the standard ones.
