diff --git a/bacnet-stack/demo/object/bo.c b/bacnet-stack/demo/object/bo.c
index de4f6c35..b33b70ac 100644
--- a/bacnet-stack/demo/object/bo.c
+++ b/bacnet-stack/demo/object/bo.c
@@ -285,12 +285,12 @@ int Binary_Output_Encode_Property_APDU(
                 object_index =
                     Binary_Output_Instance_To_Index(object_instance);
                 if (array_index <= BACNET_MAX_PRIORITY) {
-                    if (Binary_Output_Level[object_index][array_index] ==
+                    if (Binary_Output_Level[object_index][array_index-1] ==
                         BINARY_NULL)
                         len = encode_application_null(&apdu[apdu_len]);
                     else {
                         present_value =
-                            Binary_Output_Level[object_index][array_index];
+                            Binary_Output_Level[object_index][array_index-1];
                         len =
                             encode_application_enumerated(&apdu[apdu_len],
                             present_value);
diff --git a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
index ada59700..23089a0a 100644
--- a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
+++ b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
@@ -351,7 +351,7 @@ int Binary_Output_Encode_Property_APDU(
                     Binary_Output_Instance_To_Index(object_instance);
                 if (array_index <= BACNET_MAX_PRIORITY) {
                     present_value =
-                        Binary_Output_Level[object_index][array_index];
+                        Binary_Output_Level[object_index][array_index-1];
                     if (present_value == BINARY_NULL) {
                         len = encode_application_null(&apdu[apdu_len]);
                     } else {