Eddy -- thank you for offering to send me that PDF -- I have emailed you. Can't wait to get it!
General update -- I called Miele again and got a different rep who was able to talk me through something (I guess the first guy was just new and didn't know how?). I did what he said, it went into programming mode, he adjusted it to "P3" and said it should use a higher water level now. But I am not seeing anything different??? I have tried different cycles, sensitive on, sensitive off, and it looks like the exact same amount of water to me (no water line visible). Hopefully I can sort this out with Eddy's PDF... wish Miele would just unclassify the top secret instructions!
And for future searching fun... I am documenting the button sequence I pressed here (on a Miele W1215):
1. Start with washer "off" with no lights on display
2. Hold down start button
3. With start button held down, press the on/off button once.
4. Keep start button down until you see a small dot appear in the display.
5. Immediately let go of the start button, then press the start button 5 times. On the 5th time, keep it held down until the green light next to it flashes, then let go. You should now be in programming mode.
6. Display should flash "P" and "0" alternately.
(Here's where the memory is a bit fuzzy... but this is what I recall)
7. Press buzzer button once -- display moves to P1
8. Press buzzer button again -- display moves to P2
9. Press start button once -- display moves to P3
10. Press on/off switch to turn off the washer and save the setting.