title: Change total and tax_total Woocommerce
body: <p>I create custom checkout page with custom calculation. How i cant change total and tax_total via Ajax (or refresh page if need).</p>
  
  <p>I create custom page for ajax request and set this code </p>
  
  <pre><code>$ss = new WC_Session_Handler();
  $ss-&gt;set('tax_total',9999999);
  $ss-&gt;save_data();
  $ss-&gt;set('total',9999999);
  $ss-&gt;save_data(); 
  
  var_dump(WC());
  </code></pre>
  
  <p>On this page i can see my changes, but 'checkout page' nothing happens (even after refresh). How can I change the arbitrary <code>total</code> or <code>tax_total</code>.</p>