The expectedMarketFeeBPS argument to a bunch of functions is a user projection. The actual fee is a static value set by the admin, not a dynamic one, so the difference between the two values should be returned, as is done for some of the other token transfers in this contract.
There are 5 instances of this issue:
https://github.com/code-423n4/2022-05-rubicon/blob/8c312a63a91193c6a192a9aab44ff980fbfd7741/contracts/RubiconRouter.sol#L194-L199
