diff --git a/src/interfaces/ISubscriber.sol b/src/interfaces/ISubscriber.sol
index f2fc94df..238c88f3 100644
--- a/src/interfaces/ISubscriber.sol
+++ b/src/interfaces/ISubscriber.sol
@@ -6,14 +6,17 @@ import {PositionInfo} from "../libraries/PositionInfoLibrary.sol";
 
 /// @notice Interface that a Subscriber contract should implement to receive updates from the v4 position manager
 interface ISubscriber {
+    /// @notice Called when a position subscribes to this subscriber contract
     /// @param tokenId the token ID of the position
     /// @param data additional data passed in by the caller
     function notifySubscribe(uint256 tokenId, bytes memory data) external;
+
     /// @notice Called when a position unsubscribes from the subscriber
     /// @dev This call's gas is capped at `unsubscribeGasLimit` (set at deployment)
     /// @dev Because of EIP-150, solidity may only allocate 63/64 of gasleft()
     /// @param tokenId the token ID of the position
     function notifyUnsubscribe(uint256 tokenId) external;
+
     /// @notice Called when a position is burned
     /// @param tokenId the token ID of the position
     /// @param owner the current owner of the tokenId
@@ -22,8 +25,13 @@ interface ISubscriber {
     /// @param feesAccrued the fees accrued by the position if liquidity was decreased
     function notifyBurn(uint256 tokenId, address owner, PositionInfo info, uint256 liquidity, BalanceDelta feesAccrued)
         external;
+
+    /// @notice Called when a position modifies its liquidity or collects fees
     /// @param tokenId the token ID of the position
     /// @param liquidityChange the change in liquidity on the underlying position
     /// @param feesAccrued the fees to be collected from the position as a result of the modifyLiquidity call
+    /// @dev Note that feesAccrued can be artificially inflated by a malicious user
+    /// Pools with a single liquidity position can inflate feeGrowthGlobal (and consequently feesAccrued) by donating to themselves;
+    /// atomically donating and collecting fees within the same unlockCallback may further inflate feeGrowthGlobal/feesAccrued
     function notifyModifyLiquidity(uint256 tokenId, int256 liquidityChange, BalanceDelta feesAccrued) external;
 }
diff --git a/test/shared/FeeMath.sol b/test/shared/FeeMath.sol
index 72ad5659..bb593eeb 100644
--- a/test/shared/FeeMath.sol
+++ b/test/shared/FeeMath.sol
@@ -35,11 +35,11 @@ library FeeMath {
         (uint128 liquidity, uint256 feeGrowthInside0LastX128, uint256 feeGrowthInside1LastX128) =
             manager.getPositionInfo(poolId, address(posm), config.tickLower, config.tickUpper, bytes32(tokenId));
 
-        (uint256 feeGrowthInside0X218, uint256 feeGrowthInside1X128) =
+        (uint256 feeGrowthInside0X128, uint256 feeGrowthInside1X128) =
             manager.getFeeGrowthInside(poolId, config.tickLower, config.tickUpper);
 
         feesOwed = getFeesOwed(
-            feeGrowthInside0X218, feeGrowthInside1X128, feeGrowthInside0LastX128, feeGrowthInside1LastX128, liquidity
+            feeGrowthInside0X128, feeGrowthInside1X128, feeGrowthInside0LastX128, feeGrowthInside1LastX128, liquidity
         );
     }