All complaints against licensees or registered companies shall be filed with the board within two years after the act or omission alleged as the ground for disciplinary action or, in the case of fraud, within four years after commission of the fraudulent act or omission. The board shall file any accusation within one year after the complaint has been filed with the board, except that with respect to an accusation alleging a violation of Section 8637, the accusation may be filed within two years after the discovery by the board of the alleged facts constituting the fraud or misrepresentation prohibited by the section.