diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs
index 8ccfb9455..cca51e318 100644
--- a/lightning/src/chain/chaininterface.rs
+++ b/lightning/src/chain/chaininterface.rs
@@ -41,12 +41,12 @@ pub enum ConfirmationTarget {
 pub trait FeeEstimator {
 	/// Gets estimated satoshis of fee required per 1000 Weight-Units.
 	///
-	/// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
-	/// don't put us below 1 satoshi-per-byte).
+	/// Must return a value no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later  
+	/// round-downs don't put us below 1 satoshi-per-byte).
 	///
-	/// This translates to:
-	///  * satoshis-per-byte * 250
-	///  * ceil(satoshis-per-kbyte / 4)
+	/// This method can be implemented with the following unit conversions: 
+	///  * max(satoshis-per-byte * 250, 253)
+	///  * max(satoshis-per-kbyte / 4, 253)
 	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
 }