  We show that an integral assumption in DGLV radiative energy loss - the large
formation time assumption - is violated at high-$p_T$ for phenomenologically
relevant parameters. We further investigate the phenomenological impact of
placing a new kinematic bound on the radiated gluon transverse momentum, which
ensures that there are no contributions to the energy loss from regions of
parameter space that violate the large formation time assumption. We find that
this places a large sensitivity on the exact kinematic cutoff used, similar to
the known collinear cutoff sensitivity, indicating the theoretical need for a
rederivation of DGLV radiative energy with the large formation time assumption
relaxed in order to make rigorous predictions. We additionally find that this
large formation time cutoff dramatically reduces the size of a short pathlength
correction to the DGLV radiative energy loss, which is of phenomenological
interest in predicting suppression in small $p +A$ systems. We compute the
phenomenological predictions utilizing this large formation time cutoff in both
$p+A$ and $A+A$ collisions at the LHC, in a convolved radiative and elastic
energy loss model.
