What is the Recommended Practice on PayPal NVP API with Stopping and Refunding Subscriptions?

So I've started this little class for doing PayPal voids, refunds, and subscription cancels. My question is, what's the recommended practice? I mean, should I attempt to void the transaction, then ignore error, then refund it, and then cancel the subscription?

Note in my case, the transaction was started from a click on a PayPal Subscription button, and then it got renewed once after the 6 month period ended, and then the customer wanted a refund and to stop further subscriptions.

<?php

class Paypp {

public static function voidCard($r) {
  $asData = array(
    'METHOD' => 'DoVoid',
    'AUTHORIZATIONID' =>  @ $r['paypal_txn_id'] // tnx_id from subscr_payment IPN
  );
  return self::_sendData($asData);
}

public static function cancelSubscription($r) {
  $asData = array(
    'METHOD' => 'ManageRecurringPaymentsProfileStatus',
    'PROFILEID' =>  @ $r['paypal_subscr_profile_id'], // subscr_id from subscr_payment IPN
    'ACTION' => 'cancel'
  );
  return self::_sendData($asData);
}

public static function refundCard($r) {
  $asData = array(
    'METHOD' => 'RefundTransaction',
    'TRANSACTIONID' =>  @ $r['paypal_txn_id'],
    'REFUNDTYPE' => 'full',
    'CURRENCYCODE' => @ $r['currency'],
    'AMT' => @ $r['gross']
  );
  return self::_sendData($asData);

}

private static function _sendData($asData) {
global $config;

  $sActive = $config->PAYMENT_GATEWAY_DATA->pp->ACTIVE;
  $sURL = $config->PAYMENT_GATEWAY_DATA->pp->$sActive->NVP_URL;

  $sVersion = $config->PAYMENT_GATEWAY_DATA->pp->$sActive->NVP_VERSION;
  $sUser = $config->PAYMENT_GATEWAY_DATA->pp->$sActive->NVP_USER;
  $sPass = $config->PAYMENT_GATEWAY_DATA->pp->$sActive->NVP_PASS;
  $sSig = $config->PAYMENT_GATEWAY_DATA->pp->$sActive->NVP_SIG;

  $asExtra = array(
    'VERSION' => $sVersion,
    'USER' => $sUser,
    'PWD' => $sPass,
    'SIGNATURE' => $sSig
  );
  $asData = array_merge($asData,$asExtra);

  $asOpt = array(
    CURLOPT_HEADER => FALSE,
    CURLOPT_POST => TRUE,
    CURLOPT_RETURNTRANSFER => TRUE,
    CURLOPT_POSTFIELDS => http_build_query($asData),
    CURLOPT_VERBOSE => TRUE,
  );

  $hCurl = curl_init($sURL);

  curl_setopt_array($hCurl, $asOpt);
  $bVerifySSL = @ $config->VERIFY_SSL;
  curl_setopt($hCurl, CURLOPT_SSL_VERIFYPEER, $bVerifySSL);

  $sResponse = curl_exec($hCurl);
  curl_close($hCurl);
  return $sResponse;

}


} // end class

Through trial and error in the sandbox, I found what the workflow should be:

1. Skip void. According to a PayPal rep: "Voids are only valid for authorizations and orders, and you can't create either through a subscription."

2. Yes, refund. It runs against the txn_id, which is unique for every subscr_payment that you receive in the subscription process. So, you'll only refund the most recent subscr_payment you received on your IPN.

3. Yes, cancel subscription -- the refund alone won't do that step for you.