{
    my $r = sub {
        my $count = shift;
        return 'A' . $count . ':B' . $count;
    };

    for ( @{$retrieve_ref} ) {
        $sheet->Range( $r->( $count++ ) )->{'Value'} = $_;
    }
}
[download]

The main idea here is to make a sub that makes the value you want out of the variable you have. Since the sub is of such little use anywhere else, I've put it in a lexical scoped to a small block. I personally don't like map in void context, so I changed the loop to a for loop. There are, as always, ways to go extra terse here, but I was shooting for a modicum of readability. Gum it up however you like in your own code.