  We compare the results of the fixed-flavor scheme calculation of Laenen,
Riemersma, Smith and van Neerven with the variable-flavor scheme calculation of
Aivazis, Collins, Olness and Tung for the case of neutral-current
(photon-mediated) heavy-flavor (charm and bottom) production. Specifically, we
examine the features of both calculations throughout phase space and compare
the structure function $F_2(x,Q^2)$. We also analyze the dependence of $F_2$ on
the mass factorization scale $\mu$. We find that the former is most applicable
near threshold, while the latter works well for asymptotic $Q^2$. The validity
of each calculation in the intermediate region is dependent upon the $x$ and
$Q^2$ values chosen.
