jquery sum column if row checked

I have this table into a modal form:

<div class="form-group">
    <!-- Record list -->
    <table id="tabscarichi" class="table table-bordered table-striped" style='border-collapse: collapse;' >
        <tr style='background: whitesmoke;'>
            
            <th>Check</th>
            <th>Id</th>
            <th>Formulario</th>
            <th>EER</th>
            <th>Data FR</th>
            <th>Q.tà</th>
        </tr>

            <?php 
            $query = "SELECT * FROM registro_c_s where stato_carico='1'";
            $result = mysqli_query($conn,$query);

            while($row = mysqli_fetch_array($result) ){
                $id = $row['id'];
                $fr = $row['formulario'];
                $data = $row['data_fr'];
                $eer = $row['codice_eer'];
                $qta = $row['quantità'];
                $stato = $row['stato_carico'];
            ?>
        <tr>

            <!-- Checkbox -->
            <td><input type='checkbox' class="box" name='update[]' value='<?= $id ?>' ></td>
            
            <td><?= $id ?></td>
            <td><?= $fr ?></td>
            <td><?= $eer ?></td>
            <td><?= $data ?></td>
            <td class="qta_scarichi"><?= $qta ?></td>

        </tr>
            <?php

            }
            
            ?>
    </table>
</div> 

I'm trying to write a script to sum values of class .qta_scarichi and reporting it in another input number with .qtas class.

I tried this:

$('.box').change(function(){
   var total = 0;
   $('.box:checked').each(function(){
        total+=parseFloat($(this).parent().next('td').find('.qta_scarichi').text());
   });
   $('#qtà').val(total); 
});

But when i check some rows..nothing happen.. #qtà is the id of the input number that i want to fill..