The 31st of August 2018 is the date for submission of the next Interim payment. Within 90 days from the submission, the payment should be made ( cf. Article 4.2 of the SGA concerned). Please note that the sampling exercise can lead to a suspension of this time-limit (cf. Article II.24.5 of the FPA).
Therefore, it can be reasonably expected that, in view of the size and complexity of the payment procedure, the distribution of the interim payment will be made to IPPs in early 2019.