try to implement changePackage

zimbraSingle.php

@@ -609,7 +609,7 @@ function zimbraSingle_ChangePackage($params) {
     }
     $addonQuota = $params['configoptions']['addonQuota'] ? $params['configoptions']['addonQuota'] : 0;
     $newAddQuota = $params['configoptions']['newAddQuota'] ? $params['configoptions']['newAddQuota'] : 0;
-    $attrs['zimbraMailQuota'] = ($baseQuota + $addonQuota +$newQuota) * 1073741824;
+    $attrs['zimbraMailQuota'] = ($baseQuota + $addonQuota +$newAddQuota) * 1073741824;
     $response = $apiAccountManager->modifyAccount($params['username'], $attrs);
     if(is_a($response, 'Exception')) {
         logModuleCall(