Under Art. 104(1) EPC, each party to opposition proceedings must, as a rule, meet the costs it has incurred. However, the opposition division or board of appeal may, for reasons of equity, order a different apportionment of the costs incurred during taking of evidence or in oral proceedings. At the appeal stage Art. 16(1) RPBA (2007) also applies, allowing the board, subject to Art. 104(1) EPC, to order a different apportionment. It lists typical cases where costs arise as a result of: (a) amendments pursuant to Art. 13 RPBA (2007) to a party's case as filed pursuant to Art. 12(1) RPBA (2007); (b) extension of a time limit; (c) acts or omissions prejudicing the timely and efficient conduct of oral proceedings; (d) failure to comply with a direction of the board; or (e) abuse of procedure.

In T 133/06 the board added that Art. 104 EPC belonged to the procedural provisions and so was subject to the general principle of law that a new procedural law was immediately applicable but had no retrospective effect unless otherwise provided. Hence when deciding whether the new Art. 104 EPC is applicable in appeal proceedings initiated under EPC 1973, the board must take into consideration not only the fact that, according to the transitional provisions (see Decision of the Administrative Council 28 June 2001, OJ SE 1/2007, 197), the new Art. 104 EPC is applicable to granted patents, but also the date of the event which gives rise to the application of this article. This is the only way to give the new procedural provision an immediate application without giving it a retrospective effect.

According to the boards, the phrase "taking of evidence" used in Art. 104(1) EPC 1973 – but no longer used in Art. 104 EPC – refers generally to the receiving of evidence by an opposition division or a board of appeal (T 117/86, OJ 1989, 401; T 101/87, T 416/87, T 323/89, OJ 1992, 169; T 596/89 and T 719/93, referring to Art. 117 EPC 1973).