A time limit for payment is in principle deemed to have been observed only if the full amount of the fee has been paid in due time (Art. 8, first sentence, RFees).
However, the EPO has the discretion, where this is considered justified, to overlook any small amounts lacking without prejudice to the rights of the person making the payment (Art. 8, fourth sentence, RFees).
It is established in the jurisprudence of the boards and in the practice of the Office that a "small amount" means around 10% of the relevant fee (see e.g. T 130/82, OJ 1984, 172; J 11/85, OJ 1986, 1; T 109/86 of 20.7.1987 date: 1987-07-20). In T 343/02 of 20.01.2003 date: 2003-01-20, an underpayment of less than 2% due to the unexpected deduction of bank charges was overlooked.
In T 290/90 (OJ 1992, 368) and J 27/92 (OJ 1995, 288), by contrast, it was held in the circumstances of each case that an underpayment of 20% of the relevant fee could be considered a small amount. Among the factors which the board took into account was that this percentage would allow the provision to be applied to cases in which a party mistakenly sought to take advantage of the (then generally available) 20% language-based fee reduction.
However, these have remained isolated cases. Already in T 905/90 (OJ 1994, 306, Corr. 556), the board found that the meaning of "smallness" could best be determined by comparing the amount of shortfall with the amount of the full fee. A difference of 20% clearly could thus not, on purely arithmetical grounds, be regarded as small. It was with very small or trifling amounts that the former Art. 9 RFees 1973 (cf. Art. 8 RFees) was designed to deal so as to prevent a loss of rights where an inadvertent error of some kind had led to a slight underpayment of an amount due in respect of the relevant proceedings. This decision was confirmed in T 642/12, in which the board considered that "small amounts lacking" are to be read as "insignificant or negligible amounts". The legislator had presumed that a fee reduction of 20% pursuant to R. 6(3) EPC was not merely symbolic, but would effectively alleviate the burden of having to prepare translations. Therefore it could not have intended this fee reduction to be considered small in the sense of negligible or insignificant.
Furthermore, under the revised provisions of R. 6(3) – (7) EPC, Art. 14(1) RFees as in force from 1.4.2014 (see decision of the Administrative Council of 13 December 2013, OJ 2014, A4), the language-based fee reduction is set at 30% and applies only to the filing and examination fees and certain categories of applicant.
The question of what constitutes a "small amount lacking" has also arisen more recently in cases concerning the payment of the reduced rather than the full fee for appeal (Art. 2(1), item 11, RFees as in force from 1.4.2018) where the appellant was not entitled to the reduction. See in particular the analysis of the board in T 3023/18, and its conclusion that the underpayment of the appeal fee by about 17% was not "small" within the meaning of Art. 8, fourth sentence, RFees. According to the board, it was furthermore reasonable to assume that the legislator saw the fee reduction under Art. 2(1), item 11, RFees as being of genuine financial assistance to the listed categories of person, and not merely as symbolic. See, similarly, T 2422/18, T 2620/18).
The board in J 25/12 did not doubt that the underpayment in that case could be regarded as a small amount, but stressed that the EPO could exercise its discretion to overlook small amounts only if justified. This was not so here since the representative had been informed about the changed fee rates and invited to pay the amount lacking within a time limit – which, however, he had failed to do. The board in T 2620/18 similarly observed that there were in any event two cumulative requirements in Art. 8, last sentence, RFees, namely that the amount lacking be "small" and that overlooking it be "justified". It conceded that overlooking the underpayment might be justified in the case in hand, because the appeal fee had later been paid in full, but it could not do so because the difference between that full fee and the amount initially paid was not small.