Anyone on here know why injectors need recalibrating/coding?

Why do they lose the calibration/coding? Is it driving style? Disconnecting the battery? Age/milage related? Or a timebomb in the PCM so that Ford dealers can get some money?

param=mileage
param=service
subroutine='los'

IF mileage == <60000
&& service == >12
THEN DO los
ELSE service == <12
DO end

It seems a catch all response.

Me - "Car pulling to the left can you help me kind Ford garage?"

Highly skilled Ford Technician - "Yes of course sir, your injectors need recalibrating."