add data to array from php while loop

I have this code and I want to add data to $meta_input_array variable. When I add single data it's ok but when I want to add more than one it doesn't work

Here is my code:

<?php

$spa_products = array(
  'post_type' => 'spa_products'
);

$spa = new WP_Query( $spa_products );

if ( $spa->have_posts() ) {

  $row = 0;

  while ( $spa->have_posts() ) { $spa->the_post();

    $product_POST = 'product_' . get_the_ID();

    $product_normal_price = get_post_meta( get_the_ID(), 'spa_normal_price', true );
    $product_gold_price = get_post_meta( get_the_ID(), 'spa_gold_price', true );

    if ( !empty( $_POST[$product_POST] ) ) {

      if ( $_POST[$product_POST] === $product_normal_price ) {
        $product_package = $product_normal_price;
        $product_package_show = 'بسته معمولی';
      } elseif ( $_POST[$product_POST] === $product_gold_price ) {
        $product_package = $product_gold_price;
        $product_package_show = 'بسته طلائی';
      }

      echo '<tr>';

      echo '<td>' . get_the_title() . ' " <small>' . $product_package_show . '<small> " </td><td>' . number_format( $product_package ) . ' ریال</td>';

      echo '</tr>';

      $invoice_total[] = $product_package;

      $meta_input_array_row = 'row_' . $row++;
      $meta_input_array[] = array( $meta_input_array_row => $product_package_show );

    }
  }
}

$spa_new_order = array(
  'post_type'     => 'spa_orders',
  'post_title'    => $_POST['product_number'],
  'post_status'   => 'draft',
  'meta_input'    => $meta_input_array,
);

wp_insert_post( $spa_new_order );

?>

@ron Here is the results:

array(2) { [0]=> array(1) { ["row_0"]=> string(19) "gold" } [1]=> array(1) { ["row_1"]=> string(21) "normal" } }