  Extinction due to intergalactic grey dust has been proposed as an alternative
to accelerated expansion to account for the dimming of \s fluxes beyond $z
\simeq 0.5$. The ``replenishing'' grey dust model, although fitting the
observational data, does not seem to be based on physical assumptions. For this
reason, in this paper we propose a new grey dust model whose dust distribution
follows the comoving SFR density evolution, a reasonably established
phenomenon. This new model is compared with the updated photometric data sample
from the High Z Supernova Search Team (HZT). Also, using pairs of supernovae at
different redshifts, the possibility of any ``patchy'' distribution proposed to
explain the discrepancies between the ``high $z$'' dust model and the \s
observations at very high redshift ($z \ge 0.9$) is ruled out. Finally, the
data are compared with different models with and without dark energy and a best
fit to a universe with adimensional parameters $\Omega_{\mathrm{m0}} = 0.31$
and $\Omega_{\mathrm{\Lambda 0}} = 0.69$ is obtained, from which an age of the
universe of $t_{0} \simeq 14.6 \times 10^{9}$ years is derived. This age is
compatible with the age of the globular clusters using an equation of state
$\omega = -1$ and it obviates the need to resort to any kind of phantom energy.
