That'd work, but basically means duplicating the loop logic. (In part or in full.)

Update: Cleaner second loop.

But as I've already changed the routine to produce an array and return a ref to it -- 3 intermediates lists gets costly once count get over a few hundred -- tossing the coin afterward and reverseing and 'inverting' the values is a bit easier:

sub rndPart3{ ## strictly ascending, skew possible
    my( $start, $end, $count ) = @_;
    my $step = ( $end - $start ) / $count;
    my $last = $start;
    $start += $step / 2;
    my @res;
    my $lim = $count - 1;
    for( my( $i, $p ) = ( 0, $start); $i < $lim; ++$i, $p += $step ) {
        push @res, sprintf "%.2f", $last = $last + ( rand( $p + $step/
+2 - $last ) );
    }
    if( rand() < 0.5 ) {
        for( my( $s, $e ) = ( 0, $#_ ); $s <= $e; ++$s, --$e ) {
            my $temp = $end - $_[ $s ]; 
            $_[ $s ] = $end - $_[ $e ]; 
            $_[ $e ] = $temp; 
        }
    }
    return \@res;
}
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Not very pleasing though!?