  This work emphasizes that the transition voltages $V_{t \pm}$ for both bias
polarities ($V${\raisebox{1.2ex}{$_{\stackrel{>}{<}}$}0}) should be used to
properly determine the energy offset $\varepsilon_{0}$ of the molecular orbital
closest to electrodes' Fermi level and the bias asymmetry $\gamma$ in molecular
junctions. Accurate analytical formulas are deduced to estimate
$\varepsilon_{0}$ and $\gamma$ solely in terms of $V_{t \pm}$. These estimates
are validated against experiments, by showing that full experimental
$I$-$V$-curves measured by Beebe et al [\prl 97, 026801 (2006)] and Tan et al
[Appl. Phsy. Lett. 96, 013110 (2010)] for both bias polarities can be
excellently reproduced.
