Administrative Instructions under the Patent Cooperation Treaty
Section 304
Invitation to Pay Fees before Date on Which They Are Due
If the receiving Office finds, before the date on which they are due, that the transmittal fee, the international filing fee (including any supplement per sheet over 30) or the search fee are lacking in whole or in part, it may invite the applicant to pay the missing amounts within one month from the date of receipt of the international application.