pulse width correction

[Jeffrey Giberstein]

In perusing some sample EFI code, I noticed that a linear function was used to
adjust injector pulse width for changes in battery voltage.  The adjustments
appeared to range from 600 microseconds to 2000 microseconds as voltage went
from 16V to 6V. 
Is it standard practice to use a linear function for this correction or is it
dependent only on the particular injector?  Does anyone know of a source of
information regarding ITO times and varying voltage can be found?

Any help would be appreciated.

Thanks,

Jeff