[raphman]

Touch and pen would generally require completely different calibrations because touch is detected by the capacitive touch screen whereas the pen position is tracked inductively.

However, I wonder why the pen calibration data is not stored on an controller on the display panel? That would absolutely make sense.

[can16358p]

Can it be like:

Pencil also has a small calibration table and when paired with a new iPad it checks and downloads that immediately.

If not, it might also be (more likely) sending whatever it senses to iPad and iPad processes that raw input with the calibration data to determine the final output.