I'm looking to buy a business class ticket BRU-BKK-BRU and I noticed that on the BRU-BKK leg there's only Flex+ available. On expert flyer however J class is still wide open in all fare brackets.

Do you think EK will open up Saver/Flex fare again closer to departure date to fill up J class or should I buy the expensive tickets now? (in Y saver/flex/flex+ is still available, in F everything is sold out)