I don't know how she does it

There are some tiny issues with my "Back to Bach."

I'm sure it's not my fault, it's certainly not the fault of the sainted Arietta. What then? Maybe God hates me. No matter how much and how furiously I practice it, the problems remain.

"Play each key right in the middle," Tiina instructs.

Yeah, yeah, I know.

"No, really -- right in the middle. Think about it while you're doing it. Go as slow as you need to."

I am outwardly compliant, inwardly "whatever." I play the offending passage suuuuper-slooooooowly, taking elaborate care to hit each key just exactly so, smack-dab in the middle. There -- now are you happy?

"Now just play it," Tiina says.

If accordions could roll their eyes like teenagers, mine would. But we humour her.

Oh. My. God.

"I don't know why it works," Tiina says, "but it does."

How does she do it?