diff --git a/src/ddo/MetaData.ts b/src/ddo/MetaData.ts
index 228ebbb..f2690d8 100644
--- a/src/ddo/MetaData.ts
+++ b/src/ddo/MetaData.ts
@@ -276,7 +276,14 @@ export interface MetaData {
     additionalInformation?: AdditionalInformation
     curation?: Curation
 }
-
+/** Warning.  serviceIndex is the index of a services in Services array, and not service.index attribute.
+Let's assume that you have the following services array:
+[
+      {"index":1,"type":"access","main":{"price":3}},
+      {"index":0,"type":"compute","main":{"price":1}}
+]
+then calling update with { serviceIndex:1,price:2} will update the 'compute' service, and not the access one
+**/
 export interface ServicePrices {
     serviceIndex: number
     price: string