Need a hint here -- Hope someone understands...  I've been trying to dial in my KFWDKMSN. 

This shouldn't be so difficult, but I'm logging with Durametric (piece of shit software) because I have a Porsche (ME 7.8.4) and not aware of any better options.  One of the most frustrating aspects is Durametric's logged variable titles, which don't correlate to any of the variables in the FR.  So, I'm left trying to figure out exactly what I'm logging.  Example... Mass Air Flow "HFM" could be MSHFM, but it appears to be normalized for standard conditions, which may or may not be the same as the atypical standard conditions in the FR (0 degrees C and 1013 hPa).  (Aside: most engineering designs consider standard conditions to be "standard day", which is a temp of 15C -- making an enormous difference in atmospheric air density.)  I believe the Durametric number is normalized because I can log HFM raw voltage via Durametric and MLHFM translation yields materially different numbers at steady state operating conditions (little if any transient averaging effect from the ECU).  So some normalization is occurring.  I haven't tried to determine the amount of difference yet, but obviously need to do so.

I've phoned Durametric and asked for more information, but they weren't able or were unwilling to help.  Their advice... "Work with you tuner".  Since most of us here are of like mind regarding tuners and the cloak of secrecy, you can imagine my response.

Alright, rant over.  Here is the issue I'm facing...  How should you tune KFWDKMSN above the point the engine is capable of making boost?  Look at the chart I've attached and you'll see that derived flow, which I'm calculating via Excel using KFWDKMSN and MSLG (correcting with FTVDK & FPVDK not necessary since the HFM value is already standardized), begins to deviate significantly above about 128 kg/h.

Question - Am I missing a correction in my derivation of MSDK that would normalize across the range of boost?  The FR says to assume PSPVDKUG for MSDK, but I could be misunderstanding.  If so that would be a valid correction (if only my PSPVDK was accurate -- larger turbos & higher wastegate cracking pressure make it suspect).  Or, do I need to tune only for a closed or open wastegate (either end of the spread)?  It appears the OEM KFWDKMSN is based on 100% WGDC, and maybe that is the answer, but then the HFM signal is almost always below the calculated mass flow and that just doesn't seem like a good design for a backup to an HFM failure.

Maybe another way to ask this question is, "How do MAFLESS tunes account for mass air flow over the boost range"?