The natspec comments of the EvolvingProteus.withdrawGivenInputAmount function states that the feeDirection of the function to be used is FEE_UP. The reason for using FEE_UP is described as wanting to increase the perceived amount of reserve tokens leaving the pool; however, the feeDirection is determined by the protocol to benefit itself. The withdrawGivenInputAmount transaction will benefit the protocol if the perceived amount of reserve tokens leaving the pool is decreased, which is equivalent to charging a fee from the withdrawing amount.
The logic implementation of the withdrawGivenInputAmount function has implemented this requirement correctly, as shown below:
It is recommended to update the natspect comments of the withdrawGivenInputAmount function to state that the feeDirection used for the withdrawGivenInputAmount transaction is FEE_DOWN, by providing it with the proper reason to do so.
https://github.com/code-423n4/2023-08-shell/blob/main/src/proteus/EvolvingProteus.sol#L459-L461
https://github.com/code-423n4/2023-08-shell/blob/main/src/proteus/EvolvingProteus.sol#L478-L485
