无法获得先前的tr输入值

Question

关于选中上一个表tr的值的一点表白。

我想获取上一个tr输入值的值，但它总是返回下一个tr值。我们正在选中其他元素更改事件的复选框。

我的代码如下：

/*
Here i want to get value of tr instead of click because 
we have many conditions and I can't explain them all here 
*/
$('body').on('change', '.change_product_price', function() {
  var test1 = $(this).parent().parent().closest('tr').find('.chkIt').val();
  console.log(test1)
});

$('.chkIt').click(function() {
  if ($(this).is(':checked')) {
    $(this).parent().parent().find('.change_product_price').val('1');
    $(this).parent().parent().find('.change_product_price').change();
  } else {
    $(this).parent().parent().find('.change_product_price').val('0');
    $(this).parent().parent().find('.change_product_price').change();
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<table>
  <tr class="product_row">
    <td class="small-check SerialNumber"><input class="chkIt" type="checkbox" name="products[product_id][]" value="76" qty="0" product_weight="0"></td>
    <td data-th="Product Name" class="fourth_i1">8 PACK SPECIALIST EMBOSSED SILVER FOIL 500 SHEET BOX 12CM X 20CM</td>
    <td data-th="Part Number" class="grid-text">EMBOSS-Pre-Cut x 8 Pack</td>
    <td class="small-check MarkGift"><input class="chkItg" type="checkbox" name="gift[product_id][]" value="78"></td>
    <td data-th="Quantity" class="grid-text">
      <select name="products[quantity][78][]" class="change_product_price">
        <option>0</option>
        <option>1</option>
        <option>2</option>
        <option>3</option>
      </select>
      <input type="hidden" class="promo_min_quantity" name="promo_min_quantity" value="">
      <input type="hidden" class="promo_free_units" name="promo_free_units" value="0">
    </td>
  </tr>

  <tr class="product_row">
    <td class="small-check SerialNumber"><input class="chkIt" type="checkbox" name="products[product_id][]" value="78" qty="0" product_weight="0"></td>
    <td data-th="Product Name" class="fourth_i1">8 PACK SPECIALIST EMBOSSED SILVER FOIL 500 SHEET BOX 12CM X 20CM</td>
    <td data-th="Part Number" class="grid-text">EMBOSS-Pre-Cut x 8 Pack</td>
    <td class="small-check MarkGift"><input class="chkItg" type="checkbox" name="gift[product_id][]" value="78"></td>
    <td data-th="Quantity" class="grid-text">
      <select name="products[quantity][78][]" class="change_product_price">
        <option>0</option>
        <option>1</option>
        <option>2</option>
        <option>3</option>
      </select>
      <input type="hidden" class="promo_min_quantity" name="promo_min_quantity" value="">
      <input type="hidden" class="promo_free_units" name="promo_free_units" value="0">
    </td>
  </tr>

  <tr class="product_row">
    <td class="small-check SerialNumber"><input class="chkIt" type="checkbox" name="products[product_id][]" value="125" qty="0" product_weight="0"></td>
    <td data-th="Product Name" class="fourth_i1">8 PACK SPECIALIST EMBOSSED SILVER FOIL 500 SHEET BOX 12CM X 20CM</td>
    <td data-th="Part Number" class="grid-text">EMBOSS-Pre-Cut x 8 Pack</td>
    <td class="small-check MarkGift"><input class="chkItg" type="checkbox" name="gift[product_id][]" value="125"></td>
    <td data-th="Quantity" class="grid-text">
      <select name="products[quantity][125][]" class="change_product_price">
        <option>0</option>
        <option>1</option>
        <option>2</option>
        <option>3</option>
      </select>
      <input type="hidden" class="promo_min_quantity" name="promo_min_quantity" value="">
      <input type="hidden" class="promo_free_units" name="promo_free_units" value="0">
    </td>
  </tr>
</table>

这是我目前已勾选的每个tr输入76, 78 and 125的3个值

问题是我已经检查了最后的$ 227.60复选框，但返回值为$ 174.40