Confused Signals from MRC on Impact

It was a simple question: does the MRC require an Impact Plan (or 'Pathways to Impact', as they're now called), as all the other Research Councils do? The EAA Guidance suggests that in the Justification of Resources you 'need to justify any resources requested to support the impact plan', and the Applicants Handbook has a whole section on how the assessors are going to be checking on societal and economic impact.
But after some digging, and uncertain 'we'll get back to you's when I phoned the MRC, the message came back: no Impact Plan is needed, though the Case for Support does need to give a nod to impact. The sense I get is that the MRC are not entirely on board with the impact agenda, and take the impact of their research as a given.
It will be interesting to see what happens when they go over to JeS system in the autumn, though...