(call_time=1000) + (allocate_names=150) + (copy_values=250) + (extra_bit_a=15) 

versus

(call_time=1000) + (allocate_names=150) + (copy_values=250) + (the_extra_bit=5)

##</code><code>##

sub process {
    my( $AoA,  $thingToProcess ) = @_;

    $AoA->[ $thingToProcess ][ 3 ] = $AoA->[ $thingToProcess ][ 1 ] 
                                   * $AoA->[ $thingToProcess ][ 2 ];
    ...
    return;
}

...

process( $AoA, 123 );

##</code><code>##

## Use meaningful names obviously!!
use constant { 
    0 => FIRST, 1 => SECOND, 2 => THIRD, 3 => FOURTH, 
    4 => FIFTH, 5 => SIXTH, 6 => SEVENTH 
};

sub process( 
    our @s;
    local *s = shift;
    $s[ FOURTH ] = $s[ SECOND ] + $s[ THIRD ];
    ...
    return;
}    

process( $AoA[ $thingToProcess ] );