title: WooCommerce Subscriptions - change add to cart button text only when switching subscription
body: <p>I want to know how to change the text of the add to cart button on the product page only when switching subscription? I actually made it work, but the standard 'Sign up now' text (within the standard woocommerce subscriptions options) is overriding the text after a second. I am now using this code:</p>
  <pre><code>add_filter( 'woocommerce_product_single_add_to_cart_text', 'custom_add_to_cart_label_for_subscription_products', 10, 2 );
  function custom_add_to_cart_label_for_subscription_products( $var, $instance ) {
      global $product;
      $product_type = $product-&gt;get_type();
      if ( isset( $_GET['switch-subscription']) ) {
          return __( 'Wijzig abonnement' );
      } else {
          return $var;
      }
  }
  </code></pre>
  <p>So it looks like the code is working, but getting overruled or something.. How to give this code the highest priority so it overrules the standard 'Sign up now' text?</p>