For the last fifteen years I have been a SSAFA caseworker. Some three years ago I had occasion to visit a WW2 ex RAFVR Flt Lt. The talk got around to his service flying Lancs. I asked how many tours he had done and it turned out to be two and a half. He showed his logbook in which was a copy of his immediate award of a DFC with the chain of command's recommendations, finally approved by Bomber Harris. I said "did you go to Berlin?" "Yes, ten times" as his log book indicated. "But I probably went another six or seven as a trainer" which he explained was when a new crew arrived he, and presumably other experienced pilots on the squadron, would fly with them to show them the ropes but as they were not part of the official crew didn't put the mission in their log books. From what he said, he could well have flown the equivalent of another full tour as a passenger. It wasn't only on the Berlin missions.
Unfortunately, he was a very private person and according to his wife, to her knowledge, had never spoken of his wartime experiences. He needed help from RAFBF but refused to let me contact them on his behalf so the case was dropped.
A real honour to meet such a guy..