Replaced screen kobo libra colour VCOM code mismatch?

I replaced the screen of my kobo with a IFIXT genuine screen. To calibrate the screen you have to check the VCOM numbers. The firmware states "-1431 mV" and on the digitizer cable , both te ORGINAL and the IFIXIT replacement showes "1.45". That's odd: the orginal screen has another VCOM number than the firmware.

That leads to 2 questions:

1. do I have to change, after switching screeens, the VCOM of my device to "-1450"?
2. Or, since the orginal SCREEN had the same VCOM number as the REPLACEMENT screen, I do not have to change VCOM on the device?

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