89 An entity shall allocate a change in the transaction price entirely to one or more,
but not all, performance obligations or distinct goods or services promised in a series that forms part of a single performance obligation in accordance with
paragraph 22(b) only if the criteria in paragraph 85 on allocating variable
consideration are met.
90 An entity shall account for a change in the transaction price that arises as a
result of a contract modification in accordance with paragraphs 18–21.
However, for a change in the transaction price that occurs after a contract
modification, an entity shall apply paragraphs 87–89 to allocate the change in
the transaction price in whichever of the following ways is applicable:
(a) An entity shall allocate the change in the transaction price to the
performance obligations identified in the contract before the
modification if, and to the extent that, the change in the transaction
price is attributable to an amount of variable consideration promised
before the modification and the modification is accounted for in
accordance with paragraph 21(a).
(b) In all other cases in which the modification was not accounted for as a
separate contract in accordance with paragraph 20, an entity shall
allocate the change in the transaction price to the performance
obligations in the modified contract (ie the performance obligations that
were unsatisfied or partially unsatisfied immediately after the
modification).