Dyno chart help

[sean350z]

My setup:

S15 SR20det SpecR 15psi
Stock MAF, Injectors, Manifolds
NGK BK 7s (gapped 30)
FMIC
Walboro
SAFC

The dyno



Blue - No SAFC settings A/F Ratio high point = 15.6 @ 4300
Green - SAFC settings (see below)

Throttle - 10% Low (no settings on points) 50% High (settings below)

2800 - +2
3400 - +3
4000 - +6
4600 - +7
5200 - +7
5800 - +7
6400 - +7
7000 - +7
7600 - +8

Questions - When we tried to increase fuel at 4000 rpm past a certain point the engine would hiccup. Is this because of the stock MAF? Also are these A/Fs not very accurate b/c of they used a tailpipe sniffer? I'm very very impressed with the highest torque values even at 3700 rpm but everything seems to fall off around 5800 rpm. Why the hell would the SAFC settings make me loose 20hp and around 10ft/lbs?

Thanks