diff --git a/Invoice-protocol.md b/Invoice-protocol.md
index 08180b0..fb41392 100644
--- a/Invoice-protocol.md
+++ b/Invoice-protocol.md
@@ -1,8 +1,12 @@
 # Invoice protocol
 ## Rules
-1. If a payment was made, but the funds were not sufficient, the funds will be sent back.
-2. If a payment was made, but it was not in time, it will be sent back.
-3. If a payment was made, the expiration timer will be paused.
+1. If a payment was made, but the funds sent were not sufficient, the funds will be sent back.
+2. If a payment was made, but the funds sent were too much, the rest will be sent back.
+3. If a payment was made, but it was not in time, it will be sent back.
+4. If a payment was made, the expiration timer will be paused.
+
+**Note:** If a payment is sent back, the fee will be subtracted from the transcation.
+
 ## Creation
 ### 1. Submit a invoice request
 The first step is to tell LibrePay that you want to create a new invoice by submitting all necessary details.