According to the case law of the boards of appeal, the use of a fresh argument in a decision still based on grounds and evidence communicated beforehand is not precluded.
The board pointed out in T 268/00 that the right to be heard pursuant to Art. 113(1) EPC 1973 only precluded a decision's being taken on the basis of fresh evidence and grounds, while the use of a fresh argument, here based on a particular technical opinion, in a decision still based on grounds communicated beforehand was not precluded. Hence the technical argument in the decision under appeal addressed by the appellant, whether fresh or not, did not violate any of the appellant's rights. As to the technical substance of that argument, whilst the appellant might neither agree with the finding of the examining division nor with the technical argument given, a divergence of views between the examining division and the appellant on the substantive issue of inventive step did not amount to a procedural violation. See also T 1557/07, T 815/08.
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_iv_b_2_8_5.htm
Date retrieved: 17 May 2021