In T 11/82 (OJ 1983, 479) it was stated that it was not inevitable that the addition of a discussion of the advantages of the invention with reference to the prior art would constitute a contravention of Art. 123(2) EPC 1973. In T 37/82 (OJ 1984, 71), for example, a technical feature was clearly disclosed in the original application but its effect was not mentioned or not mentioned fully. It could however be deduced from the original application on the basis of normal expert considerations.
The Guidelines H-V, 2.2 (June 2012 edition) state that amendment by the introduction of further examples should always be looked at very carefully in the light of the general considerations. The same applies to the introduction of statements of new (i.e. previously not mentioned) effects of the invention such as new technical advantages. Under certain circumstances, however, later filed examples or new effects, even if not allowed into the application, may nevertheless be taken into account by the examiner as evidence in support of the patentability of the claimed invention.