259. Where the receiving Office finds that, by the time they are due under Rules 14.1(c), 15.3 and 16.1(f), no fees were paid, or the amount paid is not sufficient to cover the transmittal fee, the international filing fee and the search fee, it invites (Form PCT/RO/133) the applicant to pay the amount required to cover those fees within one month from the date of the invitation and sends to the International Bureau a copy of that invitation (Rule 16bis.1(a)).
262. Where the receiving Office issues an invitation under Rule 16bis.1(a) to pay fees after the date on which they are due and it has received moneys from the applicant before the due date, it informs the applicant to which fees those moneys have been applied (Section 320). For the application to fees due of moneys received, see Section 321 and paragraph 266. Form PCT/RO/133 is used for that purpose.
263. Any payment received by the receiving Office before the invitation (Form PCT/RO/133) is issued must be considered as having been received before the expiration of the applicable time limit. In other words, if the payment received covers the total amount due, no invitation should be sent and no late payment fee should be required; if the payment received covers only part of the total amount due, an invitation should be sent in respect of the recalculated missing amount and a late payment fee calculated on that missing amount may be required.
264. Late Payment Fee. When inviting (Form PCT/RO/133) the applicant to pay fees after the date on which they are due, the receiving Office may (but is not obliged to) require the applicant to pay a late payment fee. The amount of the late payment fee depends on the amount of the unpaid fees indicated in the invitation to pay: it is 50% of the unpaid amount, subject to minimum and maximum amounts. The minimum is equal to the transmittal fee and applies where the unpaid amount of fees is less than the amount of the transmittal fee; the maximum is equal to 50% of the international filing fee corresponding to 30 sheets (even if the international application contains more than 30 sheets) and must be calculated on the basis of the international filing fee as reduced, where applicable, under items 4 and/or 5 of the Schedule of Fees (Rule 16bis.2 and Schedule of Fees).
265. The invitation procedure (under Rule 16bis) described above does not apply to any other fee payable to the receiving Office, in particular, not to the fee due for preparing and transmitting a priority document to the International Bureau.