Prazo de entrega por faixa de dias na tabela de frete offline

functions.php

<?php
add_filter( 'wc_table_shipping_rate', 'wcts_delivery_time_range', 10, 2 );
function wcts_delivery_time_range( $rate, $raw ) {
  $percentage = 60;
  $value      = intval( ( $percentage / 100 ) * $raw['delivery_time'] );
  $value      = 0 >= $value ? 1 : $value;

  if ( $value !== $rate['label'] ) {
    $rate['label'] = str_replace( '{initial_days}', $value, $rate['label'] );
  }

  return $rate;
}