Financial liability vs Contingent liability

Question :
Skye faces a claim for infringement of the intellectual property rights of a competitor company. On 31 May 2017, Skye agreed to settle the claim and has paid $15 million to the competitor plus a variable amount of 2% based upon future sales. The variable amount represents compensation for the use of the intellectual property in the past (0·5%) and for its use in the future (1·5%).

Suggested answer :
The future sales-linked compensation is a mechanism for determining the amount of past and future use of the intellectual property. Therefore because part of the settlement is a variable amount to pay for past usage (even though
this is based on future sales) Skye should recognise a financial liability under IFRS 9 at 31 May 2017. It is a present obligation as a result of a past event and this principle is the basis of the definition of a liability not only in the ED but
also in the existing Conceptual Framework.

As regards the sales-linked payment relating to future use, the liability arises
as new sales are realised and represents an executory contract under IAS 37 Provisions, Contingent Liabilities and Contingent Assets. In these circumstances, Skye should not recognise a liability as the variable amount is based upon future sales, unless the executory contract is deemed to be onerous.

My question is whether I can argue that the variable amount related to past use of IP rights is a contingent liability as the payment is based on future sales, i.e. occurrence of uncertain future event?

Since the examiner has treated this as a financial liability, I’m not sure whether it is wrong if I classify it as contingent liability.

Hope sir could help on this, thank you very much.