IFR Table and Boost

What value does the PCM use for IFR in boost stuations as the table only goes up to atmospheric? I'm referring to a non boost referenced sloped setup in COS3. Does it just use the last value in the table or does it extrapolate? The Mag tune that came with my Radix had a flat IFR table for my returnless non referenced system?? Although I changed this, I don't know if it would make much difference because the table does not provide for boost. It appears that the only way to compensate for the reduced IFR is through the Boost VE table(automatically with AutoVE).

I am in the process of converting to a referenced return style fuel system and will be switching back to a flat IFR table. I assume that in this case the PCM will continue to use the single value from the table under boost conditions.

Thanks

Sounds like you've pretty much got it. Boost referenced regulator / flat IFR is the simple way to go, except for paying for it, of course.