The time and place of examination pursuant to the provisions of section
6420
(e)(2),
6421
(g)(2),
6427
(j)(2), or
7602 shall be such time and place as may be fixed by the Secretary and as are reasonable under the circumstances. In the case of a summons under authority of paragraph (2) of section
7602, or under the corresponding authority of section
6420
(e)(2),
6421
(g)(2), or
6427
(j)(2), the date fixed for appearance before the Secretary shall not be less than 10 days from the date of the summons.