(b) the Contractor shall send further interim claims at monthly intervals, giving the
accumulated delay and/or amount claimed, and such further particulars as the
Engineer may reasonably require; and
(c) the Contractor shall send a final claim within 28 days after the end of the effects
resulting from the event or circumstance, or within such other period as may be
proposed by the Contractor and approved by the Engineer.
Within 42 days after receiving a claim or any further particulars supporting a previous
claim, or within such other period as may be proposed by the Engineer and approved
by the Contractor, the Engineer shall respond with approval, or with disapproval and
detailed comments. He may also request any necessary further particulars, but shall
nevertheless give his response on the principles of the claim within such time.
Each Payment Certificate shall include such amounts for any claim as have been
reasonably substantiated as due under the relevant provision of the Contract. Unless
and until the particulars supplied are sufficient to substantiate the whole of the claim,
the Contractor shall only be entitled to payment for such part of the claim as he has
been able to substantiate.
The Engineer shall proceed in accordance with Sub-Clause 3.5 [Determinations] to
agree or determine (i) the extension (if any) of the Time for Completion (before or after
its expiry) in accordance with Sub-Clause 8.4 [Extension of Time for Completion],
and/or (ii) the additional payment (if any) to which the Contractor is entitled under the
Contract.
The requirements of this Sub-Clause are in addition to those of any other Sub-Clause
which may apply to a claim. If the Contractor fails to comply with this or another Sub-
Clause in relation to any claim, any extension of time and/or additional payment shall
take account of the extent (if any) to which the failure has prevented or prejudiced
proper investigation of the claim, unless the claim is excluded under the second
paragraph of this Sub-Clause.