diff --git a/api/src/main/java/com/ning/billing/invoice/api/InvoiceUserApi.java b/api/src/main/java/com/ning/billing/invoice/api/InvoiceUserApi.java
index 91b0917..74fa8e3 100644
--- a/api/src/main/java/com/ning/billing/invoice/api/InvoiceUserApi.java
+++ b/api/src/main/java/com/ning/billing/invoice/api/InvoiceUserApi.java
@@ -163,7 +163,7 @@ public interface InvoiceUserApi {
* @param accountId account id
* @param invoiceId invoice id
* @param invoiceItemId invoice item id
- * @param effectiveDate the effective date for this adjustment invoice item
+ * @param effectiveDate the effective date for this adjustment invoice item (in the account timezone)
* @param context the call context
* @return the adjustment invoice item
* @throws InvoiceApiException
@@ -176,7 +176,7 @@ public interface InvoiceUserApi {
* @param accountId account id
* @param invoiceId invoice id
* @param invoiceItemId invoice item id
- * @param effectiveDate the effective date for this adjustment invoice item
+ * @param effectiveDate the effective date for this adjustment invoice item (in the account timezone)
* @param amount the adjustment amount
* @param currency adjustment currency
* @param context the call context