  We study the electronic current through a quantum dot coupled to two
superconducting leads which is driven by either a voltage $V$ or temperature
$\Delta T$ bias. Finite biases beyond the linear response regime are
considered. The local two-particle interaction $U$ on the dot is treated using
an approximation scheme within the functional renormalization group approach
set up in Keldysh-Nambu-space with $U$ being the small parameter. For $V>0$ we
compare our renormalization group enhanced results for the dc-component of the
current to earlier weak coupling approaches such as the Hartree-Fock
approximation and second order perturbation theory in $U$. We show that in
parameter regimes in which finite bias driven multiple Andreev reflections
prevail small $|U|$ approaches become unreliable for interactions of
appreciable strength. In the complementary regime the convergence of the
current with respect to numerical parameters becomes an issue - but can
eventually be achieved - and interaction effects turn out to be smaller then
expected based on earlier results. For $\Delta T>0$ we find a surprising
increase of the current as a function of the superconducting phase difference
in the regime which at $T=0$ becomes the $\pi$ (doublet) phase.
