diff --git a/lib/Citycom/OanApiHelper.php b/lib/Citycom/OanApiHelper.php
index 87404fe7d..ee793e0e8 100644
--- a/lib/Citycom/OanApiHelper.php
+++ b/lib/Citycom/OanApiHelper.php
@@ -116,10 +116,12 @@ class Citycom_OanApiHelper {
 
         $this->log->debug(print_r($want_services, true));
 
+        $allowed_service_types = array_merge(CITYCOM_OAN_API_SERVICES_FOR_ORDER, CITYCOM_OAN_API_SERVICES_FOR_RESERVATION);
+
         // check if we have these services already
         foreach($cc_service_types as $stype) {
-            if(!in_array($stype->name, CITYCOM_OAN_API_SERVICES_FOR_ORDER)) continue;
-            $ctag_service_type = array_flip(CITYCOM_OAN_API_SERVICES_FOR_ORDER)[$stype->name];
+            if(!in_array($stype->name, $allowed_service_types)) continue;
+            $ctag_service_type = array_flip($allowed_service_types)[$stype->name];
             if(PreorderCtag::getFirstActive(["preorder_id" => $preorder->id, "service_type" => $ctag_service_type])) {
                 // service was ordered already, remove from want_services
                 unset($want_services[$ctag_service_type]);