As said right now the blower is disconnected and I only have a FIPK filter (similar to the blackwing filter for the corvette).
VE table is stock, Timing table is stock (28* at WOT), MAF table is stock.
Only the IFR table has been changed, but at WOT I saw a constant MAP so the PCM is always using the same IFR value.

That the measured AFR is lower than the "commanded" is not so strange (IFR is maybe still not right), I just don't understand why it makes a slope. Like if the MAF was seeing more air than what it was.

Unless there are other factors that influences fueling that I don't see in Edit.
There is a PE vs coolant temperature, but at 200F the correction is zero.
The measured timing was also 28* without KR.

I know: the AFR is not too much out and I could correct it in the PE vs RPM table and call it a day. I just was wondering why it's a curve and not a line...

Thanks - Stefano