As set out in the legislation, within 120 days of the fixed election date, members of parties that have an MP in the House would be able to request that the PBO make election-costing proposals on their behalf. That's set out in the legislation. There are rules around it to ensure that you can ask for a costing of something and it is not required that it be part of your platform. It's part of helping parties to develop an effective platform, because, of course, if you were to request the costing of something and you suddenly found that it was very expensive, you should be able to step away from it. You should be able to make the choice not to release that.
On May 11th, 2017. See this statement in context.