4.6.4. Exceptions to the Federal Rule.The federal courts’ universal preference for the before and after method makes clear that departures may be appropriate, if at all, only in “very unique and complex” circumstances.848 “[A]ny other method of arriving at compensation could conceivably arrive at something else, either more or less, than compensation.”849 Nevertheless, some federal courts have accepted valuation methods other than the before and after rule in partial acquisitions where necessary to reach a fair and practical result.850 But in those unusual circumstances, as the Court of Claims warned, “[t]he particular evaluation approach utilized by a party in severance damage situations can sometimes serve to increase the burden it must carry in persuading that speculation and conjecture are not the essence of its presentation.”851