A previous post discussed the issue of Design Choice and the Patent Office's strategy of ignoring claim elements on the theory that they are obvious design choices because the specification does not discuss any particular advantage for the missing limitation in the prior art. Of course, it is impossible to always have such disclosure as one never know what element will be missing from the cited art and why the the difference from what is shown contributes to providing a technical advantage. Thus, case law has made clear that such explanations and reasoning can be provided after the application was filed and need not be disclosed in the specification.
Similar to this point, the MPEP actually explains how such advantages could be added directly to the specification without running afoul of the new matter prohibition. MPEP 2163.07(a) explains what it refers to as the Inherent Function, Theory, or Advantage.
By disclosing in a patent application a device that inherently performs a function or has a property, operates according to a theory or has an advantage, a patent application necessarily discloses that function, theory or advantage, even though it says nothing explicit concerning it. The application may later be amended to recite the function, theory or advantage without introducing prohibited new matter. In reReynolds, 443 F.2d 384, 170 USPQ 94 (CCPA 1971); In reSmythe, 480 F. 2d 1376, 178 USPQ 279 (CCPA 1973). “To establish inherency, the extrinsic evidence ‘must make clear that the missing descriptive matter is necessarily present in the thing described in the reference, and that it would be so recognized by persons of ordinary skill. Inherency, however, may not be established by probabilities or possibilities. The mere fact that a certain thing may result from a given set of circumstances is not sufficient.’” In re Robertson, 169 F.3d 743, 745, 49 USPQ2d 1949, 1950-51 (Fed. Cir. 1999) (citations omitted).
While one must be cautious, particularly with regard to providing theories, the notion that an advantage that necessarily results from a disclosed structure may be helpful in those cases where an examiner insists (improperly) that an advantage relied upon to overcome Design Choice must be present in the specification. Since the applicant has likely already argued that the particular advantage is present and linked to certain claimed features (and thus would be estopped for asserting infringement against a product not able to achieve said advantage), adding it to the specification would seem no more disadvantageous and may carry sufficient weight with the examiner to avoid an appeal and obtain allowance without further expense and delay.