diff --git a/bacnet-stack/ports/atmega168/h_rp.c b/bacnet-stack/ports/atmega168/h_rp.c
index d9910b1b..f8ec7c29 100644
--- a/bacnet-stack/ports/atmega168/h_rp.c
+++ b/bacnet-stack/ports/atmega168/h_rp.c
@@ -96,6 +96,7 @@ void handler_read_property(
     BACNET_READ_PROPERTY_DATA data;
     int len = 0;
     int ack_len = 0;
+    int property_len = 0;
     int pdu_len = 0;
     BACNET_NPDU_DATA npdu_data;
     bool error = false;
@@ -129,15 +130,14 @@ void handler_read_property(
             &Handler_Transmit_Buffer[pdu_len],
             service_data->invoke_id, &data);
         /* FIXME: add buffer len as passed into function or use smart buffer */
-        len = Encode_Property_APDU(
+        property_len = Encode_Property_APDU(
             &Handler_Transmit_Buffer[pdu_len + ack_len], data.object_type,
             data.object_instance, data.object_property, data.array_index,
             &error_class, &error_code);
         if (len >= 0) {
-            pdu_len = pdu_len + len + ack_len;
             len = rp_ack_encode_apdu_object_property_end(
-                &Handler_Transmit_Buffer[pdu_len]);
-            pdu_len += len;
+                &Handler_Transmit_Buffer[pdu_len + property_len + ack_len]);
+            len +=  ack_len + property_len;
             error = false;
         }
     }
diff --git a/bacnet-stack/src/rp.c b/bacnet-stack/src/rp.c
index 6aa36ecf..e8764efa 100644
--- a/bacnet-stack/src/rp.c
+++ b/bacnet-stack/src/rp.c
@@ -133,19 +133,23 @@ int rp_ack_encode_apdu_init(
         apdu[2] = SERVICE_CONFIRMED_READ_PROPERTY;      /* service choice */
         apdu_len = 3;
         /* service ack follows */
-        apdu_len +=
-            encode_context_object_id(&apdu[apdu_len], 0, 
+        len =
+            encode_context_object_id(&apdu[apdu_len], 0,
             rpdata->object_type, rpdata->object_instance);
-        apdu_len +=
+        apdu_len += len;
+        len =
             encode_context_enumerated(&apdu[apdu_len], 1,
             rpdata->object_property);
+        apdu_len += len;
         /* context 2 array index is optional */
         if (rpdata->array_index != BACNET_ARRAY_ALL) {
-            apdu_len +=
+            len =
                 encode_context_unsigned(&apdu[apdu_len], 2,
                 rpdata->array_index);
+            apdu_len += len;
         }
-        apdu_len += encode_opening_tag(&apdu[apdu_len], 3);
+        len = encode_opening_tag(&apdu[apdu_len], 3);
+        apdu_len += len;
     }
 
     return apdu_len;