This is what standard IFRS 15 say About price determination
Determine the transaction price
The transaction price is the amount to which an entity expects to be entitled in exchange for the transfer of goods and services. When making this determination, an entity will consider past customary business practices. [IFRS 15:47]
Where a contract contains elements of variable consideration, the entity will estimate the amount of variable consideration to which it will be entitled under the contract. [IFRS 15:50] Variable consideration can arise, for example, as a result of discounts, rebates, refunds, credits, price concessions, incentives, performance bonuses, penalties or other similar items. Variable consideration is also present if an entity’s right to consideration is contingent on the occurrence of a future event. [IFRS 15:51]
The standard deals with the uncertainty relating to variable consideration by limiting the amount of variable consideration that can be recognized. Specifically, variable consideration is only included in the transaction price if, and to the extent that, it is highly probable that its inclusion will not result in a significant revenue reversal in the future when the uncertainty has been subsequently resolved. [IFRS 15:56]
However, a different, more restrictive approach is applied in respect of sales or usage-based royalty revenue arising from licenses of intellectual property. Such revenue is recognized only when the underlying sales or usage occur. [IFRS 15: B63]
