I consider myself not all knowing, but even I understand that if there is a base-class, which requires its derived classes to implement a method to return, for instance, the EndOfLive date for the instance of that class and one chooses to implement that method to calculate and return a date, which isn’t always the right date, and then assume that who-ever calls that method magically knows that the result should be re-calculated and converted using an obscure, undocumented correction-method, located somewhere in a undisclosed utility, outside of that class which the person created not to long ago, that there is something structurally wrong with that implementation of said method and something structurally wrong with that person in general.

If a method should return X, then don’t return Y and expect that everybody magically knows that the result needs to be converted to create X. But, FFS, return X!