If by "Volkhov" you mean Solomon of that ilk, then I'd rather move away, thanks - but I agree with the rest of what you write here, without question.
I agree that Volkhov's credibility has been questioned on a number of issues. What is tantalising, however, is that Rostropovich - in one of his typically impish moments, and
impromptu during a talk at the Conservatoire about something else - said that Volkhov was right about the dedication of the Seventh. Of course, Rostro had his own reasons to dislike the soviet regime, and to denigrate it when he got the chance. Nor did he like Khrennikov personally. Nor was this remark - allegedly made in an answer to a question after the end of his talk - on the record, and there's no official record of it. It's simply something that many people allege was said - but what exactly he said, we don't know. And the Russian Rumour-Mill works more efficiently and with greater output than all other Rumour-Mills.