(1) A period may be extended under both section 104(1) and (3).
(2) No more than one extension is possible under section 104(1).
(3) Where a relevant investigation period or a final offer period is extended or further extended under section 104(1) or (3), the period as extended or, as the case may be, further extended is, subject to subsection (4), to be calculated by taking the period being extended and adding to it the period of the extension (whether or not those periods overlap in time).
(4) Where -
(a) a relevant investigation period or a final offer period is further extended under section 104(3), and
(b) the further extension overlaps with a previous extension under section 104(3),
the period of overlap is to be disregarded in calculating the period of the further extension.