[Spinner]

In case the old combat-script is still being used...

You have all you need in the sub-routine called handle_salvage.
Add a little for-loop that goes through the shiptypes:
my $max_m_salvage=0; my $max_c_salvage=0; my $max_e_salvage=0;
for (my $i=0;$i<=$#combat_tbl ;$i++) {
$max_m_salvage+=$combat_tbl[$i]{defenders_lost}*$combat_tbl[$i]{metal};
$max_c_salvage+=$combat_tbl[$i]{defenders_lost}*$combat_tbl[$i]{crystal};
$max_e_salvage+=$combat_tbl[$i]{defenders_lost}*$combat_tbl[$i]{eonium};
}

Then after the calculation of $metal_value_of_destroyed_ships and its crystal and eonium equivalents, just force those values to be a max of the max-salvage variables.
Done deal.

OR:
Calculate the salvage from only destroyed defending ships.

Voila...