diff --git a/zip-proportional-output-fee-mechanism-pofm.rst b/zip-proportional-output-fee-mechanism-pofm.rst
index 9acfad3d..55cefe95 100644
--- a/zip-proportional-output-fee-mechanism-pofm.rst
+++ b/zip-proportional-output-fee-mechanism-pofm.rst
@@ -150,7 +150,8 @@ Specification
 
 Wallets implementing this specification will use a conventional fee in the form of 
 min_fee = base_fee * max(1, #inputs + #outputs - 4) 
-starting from block 1,800,000.
+starting from block 1,800,000 for Mainnet, or immediately on implementing this
+ZIP for Testnet.
 
 
 Transaction relaying