Modifying a tune for new injectors and adding a superchager

I have a question for all you boosted tuners....
I have done a fair amount of research on updating injector tables and its seems very straightforward. But one thing that puzzles me....
The offset and flow tables are input vs. kPa of manifold vacuum, OK, I understand that, but the tables stop at 0 vacuum (otherwise known as atmospheric pressure) but when you boost the motor you now go negative vacuum (otherwise known as boost). What does the ECM do with this injector data that stops at ZERO vacuum, does it simply extrapolate the curve as it goes into boost? Thats fine if the curve is linear like the flow curve, but the offset curves are not quite linear.

Post the tune. Some stop there and it just uses the last value, some have an OS patch that makes it go beyond that and some go beyond that from the factory. Offsets matter a lot less at higher injector pulse widths in my experience.

It won't extrapolate, it will use the last value on the table.

As schpenxel said, the offset once in boost isn't a huge deal. Offset issues are going to show themselves much more at low pulsewidth areas.

Sorry I took so long getting back to you guys, I was on vacation.
Thanks for the explanation, as long as the offsets are less important in boost then I should be able to tune for it using a tweak to my MAF calibration or VE. It would be better if my LS2 OS used the differential pressure instead of the absolute pressure. Attached is a copy of the tune.