  The time-dependent non-crossing approximation is employed for the
single-electron transistor to calculate the transient response of the
conductance for a variety of temperatures and biases. We consider the case when
the dot-lead tunneling constant is suddenly changed such that the Kondo effect
is present in the final state. In the fast non-universal timescale, which was
previously identified, we see rapid oscillations. The frequency of these
oscillations is equal to the dot level and their amplitude is modulated by the
initial and final tunneling constants. To study the slow universal timescale,
we develop a new numerical scheme. We compute the conductance for two systems
which have different Kondo temperatures down to a fraction of $T_{K}$ in
infinitesimal bias with this scheme. We conclude that universality is preserved
as a function of $T/ T_{K}$. We also investigate the decay rate of recently
identified SKP oscillations down to zero temperature and compare it with the
previous analytical results obtained with the perturbative renormalization
group.
