(1) Unless the —
(a) parties agree; or
(b) court orders otherwise,
a claimant who discontinues is liable for the costs incurred by the defendant against whom the claim is discontinued, on or before the date on which notice of discontinuance was served.
(2) If a claim is only partly discontinued —
(a) the claimant is only liable for the costs relating to that part of the claim which is discontinued; and
(b) unless the court orders otherwise, the costs which the claimant is liable to pay are not to be quantified until the conclusion of the rest of the claim.