Clearly DFC struggles with the english language - to the extent that he is unable to understand what the "Diversion" in "Distress and Diversion" stands for. If D&D are happy to help a pilot find their way to their destination then goods on them - it is, after all, part of their remit.
As DXW said, D&D would rather have people call early than have to pick up the bits later.
A question for the self-righteous:
How many of you have actually BEEN to D&D and spoken to the people there? I did whilst in the RAF and I know DXW has, too. It's a good thing to do - they can give you a very useful insight into the way they work, the service they can offer and how they would like YOU to interact with THEM.