[Cu3PO42]

I'm assuming we're referring to 70 words per minute here? In that case I'd have to agree that while 70 is plenty fast for most practical applications, it seems low for the amount of complexity involved.

For me, I don't type faster than I do because I can't consistently move my fingers faster while maintaining high accuracy. However, that is without any n-grams or other complexities.

OTOH, if you trade off required movement for mental complexity, you might bottleneck on your thinking speed instead of your finger speed. Maybe that's the reason the grandparent isn't/wasn't going faster.

[nxdmum]

Yes. I would switch over when i reached 70 words per minute.