(a) A 10-point preference eligible is entitled to file an application at any time for an examination for any position for which OPM maintains a register, for which a register is about to be established, or for which a nontemporary appointment was made in the preceding three years. For the purposes of this paragraph OPM shall hold an examination not later than the quarterly period succeeding that in which the application is filed.

(b) When there is no appropriate existing register, OPM may establish special registers containing the names of eligibles from the quarterly examinations authorized by paragraph (a) of this section, together with the names of eligibles described in § 332.322, and use these registers for certification to fill appropriate vacancies.