答案，来自工程师的答复：
That Prokofiev concerto recording was made at a very slow speed for its era, around 75 rpm, and needs a large amount of speed correction to bring the pitch to A = 440 Hz. I just checked Ward's Biddulph transfer and my Naxos transfer using my pitch-checking machine (a Korg Auto-Chromatic Tuner), and I think Ward's pitch here was a little flat. That would explain why the timing of the Biddulph is slightly longer than the Naxos. I hope that answers your question.
Yours,
Mark Obert-Thorn
