Big Bed enters in a contract with a customer to sell beds for $400 per bed on 1 January 2017. If the customer purchases more than 1000 beds in a calendar year, the contract states that the price per unit is retrospectively reduced to $380 per unit. As a result of this the consideration in the contract is variable. As at 31 March 2017, Big Bed sells 80 beds to the customer, therefore Big Bed estimates that the customers purchase will not exceed the 1000 bed threshold required for the volume discount in the calendar year. At the beginning of June 2017, the customer acquires another company and at the end of the second quarter, 30 June 2017, Big Bed sells an additional 500 beds to the customer. In light of the new fact, Big Bed estimates that the customers purchases will exceed the 1000 bed threshold for the calendar year and therefore it would have to retrospectively reduce the price per unit. Give your explanations and calculations according to IFRS 15