diff --git a/src/circles/Demurrage.sol b/src/circles/Demurrage.sol
index eb8da73..18b461e 100644
--- a/src/circles/Demurrage.sol
+++ b/src/circles/Demurrage.sol
@@ -4,7 +4,7 @@ pragma solidity >=0.8.24;
 import "../errors/Errors.sol";
 import "../lib/Math64x64.sol";
 
-contract Demurrage is ICirclesERC1155Errors {
+contract Demurrage is ICirclesDemurrageErrors {
     // Type declarations
 
     /**
@@ -142,6 +142,10 @@ contract Demurrage is ICirclesERC1155Errors {
      */
     int128[15] internal R;
 
+    // Events
+
+    event DiscountCost(address indexed account, uint256 indexed id, uint256 discountCost);
+
     // Constructor
 
     constructor() {
diff --git a/src/circles/DiscountedBalances.sol b/src/circles/DiscountedBalances.sol
index 04d16d7..173ce76 100644
--- a/src/circles/DiscountedBalances.sol
+++ b/src/circles/DiscountedBalances.sol
@@ -13,10 +13,6 @@ contract DiscountedBalances is Demurrage {
      */
     mapping(uint256 => mapping(address => DiscountedBalance)) public discountedBalances;
 
-    // Events
-
-    event DiscountCost(address indexed account, uint256 indexed id, uint256 discountCost);
-
     // Constructor
 
     /**
@@ -45,7 +41,7 @@ contract DiscountedBalances is Demurrage {
         DiscountedBalance memory discountedBalance = discountedBalances[_id][_account];
         if (_day < discountedBalance.lastUpdatedDay) {
             // DiscountedBalances: day is before last updated day
-            revert CirclesERC1155DayBeforeLastUpdatedDay(_account, _id, _day, discountedBalance.lastUpdatedDay, 0);
+            revert CirclesDemurrageDayBeforeLastUpdatedDay(_account, _id, _day, discountedBalance.lastUpdatedDay, 0);
         }
         uint256 dayDifference;
         unchecked {
@@ -82,7 +78,7 @@ contract DiscountedBalances is Demurrage {
     function _updateBalance(address _account, uint256 _id, uint256 _balance, uint64 _day) internal {
         if (_balance > MAX_VALUE) {
             // DiscountedBalances: balance exceeds maximum value
-            revert CirclesERC1155AmountExceedsMaxUint190(_account, _id, _balance, 0);
+            revert CirclesDemurrageAmountExceedsMaxUint190(_account, _id, _balance, 0);
         }
         DiscountedBalance storage discountedBalance = discountedBalances[_id][_account];
         discountedBalance.balance = uint192(_balance);
@@ -100,7 +96,7 @@ contract DiscountedBalances is Demurrage {
         DiscountedBalance storage discountedBalance = discountedBalances[_id][_account];
         if (_day < discountedBalance.lastUpdatedDay) {
             // DiscountedBalances: day is before last updated day
-            revert CirclesERC1155DayBeforeLastUpdatedDay(_account, _id, _day, discountedBalance.lastUpdatedDay, 1);
+            revert CirclesDemurrageDayBeforeLastUpdatedDay(_account, _id, _day, discountedBalance.lastUpdatedDay, 1);
         }
         uint256 dayDifference;
         unchecked {
@@ -117,7 +113,7 @@ contract DiscountedBalances is Demurrage {
         uint256 newBalance = discountedBalanceValue + _value;
         if (newBalance > MAX_VALUE) {
             // DiscountedBalances: balance exceeds maximum value
-            revert CirclesERC1155AmountExceedsMaxUint190(_account, _id, newBalance, 1);
+            revert CirclesDemurrageAmountExceedsMaxUint190(_account, _id, newBalance, 1);
         }
         discountedBalance.balance = uint192(newBalance);
         discountedBalance.lastUpdatedDay = _day;
diff --git a/src/errors/Errors.sol b/src/errors/Errors.sol
index 6548d0f..9894daf 100644
--- a/src/errors/Errors.sol
+++ b/src/errors/Errors.sol
@@ -35,14 +35,16 @@ interface IHubErrors {
     error CirclesHubNettedFlowMismatch(uint16 vertexPosition, int256 matrixNettedFlow, int256 streamNettedFlow);
 }
 
-interface ICirclesERC1155Errors {
+interface ICirclesDemurrageErrors {
     error CirclesERC1155MintBlocked(address human, address mintV1Status);
 
-    error CirclesERC1155AmountExceedsMaxUint190(address account, uint256 circlesId, uint256 amount, uint8 code);
+    error CirclesDemurrageAmountExceedsMaxUint190(address account, uint256 circlesId, uint256 amount, uint8 code);
 
-    error CirclesERC1155DayBeforeLastUpdatedDay(
+    error CirclesDemurrageDayBeforeLastUpdatedDay(
         address account, uint256 circlesId, uint64 day, uint64 lastUpdatedDay, uint8 code
     );
+
+    error CirclesERC1155CannotReceiveBatch(uint8 code);
 }
 
 interface ICirclesErrors {
@@ -58,8 +60,6 @@ interface ICirclesErrors {
 
     error CirclesInvalidParameter(uint256 parameter, uint8 code);
 
-    error CirclesERC1155CannotReceiveBatch(uint8 code);
-
     error CirclesAmountOverflow(uint256 amount, uint8 code);
 
     error CirclesArraysLengthMismatch(uint256 lengthArray1, uint256 lengthArray2, uint8 code);
diff --git a/src/lift/ERC20DiscountedBalances.sol b/src/lift/ERC20DiscountedBalances.sol
index 32f93ca..e17dee2 100644
--- a/src/lift/ERC20DiscountedBalances.sol
+++ b/src/lift/ERC20DiscountedBalances.sol
@@ -70,6 +70,9 @@ contract ERC20DiscountedBalances is ERC20Permit, Demurrage, IERC20 {
 
     function balanceOfOnDay(address _account, uint64 _day) public view returns (uint256) {
         DiscountedBalance memory discountedBalance = discountedBalances[_account];
+        if (_day < discountedBalance.lastUpdatedDay) {
+            // ERC20 DiscountedBalances: day is before last updated day
+        }
         return _calculateDiscountedBalance(discountedBalance.balance, _day - discountedBalance.lastUpdatedDay);
     }
 
@@ -83,7 +86,7 @@ contract ERC20DiscountedBalances is ERC20Permit, Demurrage, IERC20 {
     function _updateBalance(address _account, uint256 _balance, uint64 _day) internal {
         if (_balance > MAX_VALUE) {
             // Balance exceeds maximum value.
-            revert CirclesERC1155AmountExceedsMaxUint190(_account, 0, _balance, 0);
+            revert CirclesDemurrageAmountExceedsMaxUint190(_account, 0, _balance, 0);
         }
         DiscountedBalance storage discountedBalance = discountedBalances[_account];
         discountedBalance.balance = uint192(_balance);
@@ -97,7 +100,7 @@ contract ERC20DiscountedBalances is ERC20Permit, Demurrage, IERC20 {
         ) + _value;
         if (newBalance > MAX_VALUE) {
             // Balance exceeds maximum value.
-            revert CirclesERC1155AmountExceedsMaxUint190(_account, 0, newBalance, 0);
+            revert CirclesDemurrageAmountExceedsMaxUint190(_account, 0, newBalance, 0);
         }
         discountedBalance.balance = uint192(newBalance);
         discountedBalance.lastUpdatedDay = _day;