Explanation for Byron Disappointment

[XfireZ51]

I mentioned in the Byron thread that I hadn't noticed any real improvement in trap speed from my first time out with stock motor/B+B exhaust and this last trip to Byron after having installed Watson headers.
I decided to check injectors and those ohmed out fine. Nice day today s I threw on the scan tool and went for a ride just to see if headers had "leaned" things out. BLMs were in fine range of 131L/128R, typical split BLM. I made a couple of WOT bursts curious to look at NBO2 just for grins.
(I know you can't really tell. I have ZT-2 to install maybe tomorrow).
But what I did see on scan was Total SA was 23d at full tilt. Looking at the bin file, I should be getting 29d at 6000rpm/95-100kPa. There was about 4d KR but I'm also seeing a 1.8d SA relative to ref at 850rpm! SA table shows I should have 20d. Maybe I have some of the terminology wrong but even accounting for an additional 5.9d as Initial SA, the numbers don't add up. Any help is appreciated.