Under Art. 8 RFees, 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. 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.

In T 130/82 (OJ 1984, 172) the board decided that it was justified to overlook an underpayment of just over 10%. In J 11/85 (OJ 1986, 1) the board stated that an underpayment of about 10% may as a rule be considered as a small amount (see also T 109/86 of 20 July 1987 date: 1987-07-20). See also T 343/02 of 20 January 2003 date: 2003-01-20, where the underpayment of less than 2% due to the unexpected deduction of bank charges was overlooked. The board in J 25/12 did not doubt that the underpayment 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.

In the cases set out below the amount lacking corresponded to the 20% language-based fee reduction according to former R. 6(3) EPC and Art. 14(1) RFees. Under the revised provisions (in force from 1.4.2014 – see Decision of the Administrative Council of 13 December 2013, OJ 2014, A4), this reduction applies only to the filing and examination fees and certain categories of applicant, and the amount is set at 30%.

According to T 290/90 (OJ 1992, 368), whether it is justified to overlook a small amount lacking must be decided on an objective basis, having regard to all the relevant circumstances of the case, and not on a subjective basis. The board held that in the circumstances 20% of the opposition fee could properly be regarded as a small amount, because it was inappropriate to punish the appellant for contending that he was entitled to a reduction in the opposition fee (under R. 6(3) EPC 1973), and the missing 20% was paid soon after expiry of the period.

However, 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 (see now 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.

In J 27/92 (OJ 1995, 288) the examination fee was underpaid by about 20%. Distinguishing T 905/90, the board defined the concept of a "small amount lacking" as a fixed proportion of at most 20% of the amount of the fees to be paid. Moreover, the choice of 20% would achieve the desirable end of making it possible to apply the provision to cases where a party paying fees mistakenly sought to take advantage of the (now former) 20% reduction in fees available under R. 6(3) EPC 1973 and former Art. 12(1) RFees (see now Art. 14(1) RFees). In the circumstances of the case the board decided that it was justified to overlook the deficit as the applicant not only paid it without delay, but also appeared to have been misled into paying only 80% of the fees as a result of information provided by the EPO. For a different approach, see T 642/12, in which the board, following T 905/90, considered that "small amounts lacking" are to be read as "insignificant or negligible amounts".

Reference is also made to decision T 152/82 date: 1983-09-05 (OJ 1984, 301), relevant to incorrect amounts in debit orders (see in this chapter III.U.2.2. above).