I wonder how many Russian conductors in the Soviet era opted for what presumably must be called the "alternative ending" to the 'Manfred' Symphony. This entailed omitting the organ altogether in the fourth movement's pianissimo closing pages and replacing these with the fortissimo ending of the first movement. Whoever devised this version incorporated Toscanini's added tam-tam crashes while they were at it.
Here is that finale with Temirkanov and the St. Petersburg Philharmonic, taken from a DVD of the London 'Proms' performance given in 1992 at the Royal Albert Hall. It will be noted that he also made quite a few cuts in the score ...
https://www.youtube.com/watch?v=O3hXgvJOUEE
Here is Svetlanov and the USSR State Academic Symphony Orchestra from 1985, again with the 'Soviet' ending ...
https://www.youtube.com/watch?v=90vmqb9Mih0
He also did this version again in 1992 ...
https://www.youtube.com/watch?v=EqweNvTnheA
However, in this undated performance, Svetlanov and the USSR State Symphony gave the original "quiet" ending ...
https://www.youtube.com/watch?v=Zrlh_ySLSdM
I wonder if other Soviet conductors at the time used the "loud" ending. Rozhdestvensky wasn't one of them and indeed his organ entry blows your socks off, not least because he has the organ continuing to play fortissimo along with the rest of the orchestra, doubling their parts, when in the score it had actually long stopped playing! ...
https://www.youtube.com/watch?v=0Lo0m-wp3Zc&t=2459s
Incidentally, in his notes to the Temirkanov DVD, David Nice wrote that the 'Soviet ending "is particularly convincing, a rather good substitute for a glib happy end." Well that's alright then!