Looking for stuff to work on in isolation, I found a copy of Simandl 30 Etudes with piano accompaniment. I tuned up as usual, skipping the tuning notes on the CD. I was going out of my mind trying to play in tune until (D'OH) it occurred to me to check the pitch with the strobe tuner app on my phone. To my surprise, the piano is tuned to A=437. I retuned the bass, and all is well, but I wonder why MMO did this, especially without any indication of non-440 anywhere in the book.