I did some 4th gear pulls in my 2005 STi yesterday. The ONLY thing that I changed in the maps between the pulls was AVCS targets. I did the pulls back to back on the highway. Traffic was light here on the "mostly speed limit ignored" Italian highway right by my house. I have a VF39, stock airbox with silicon after MAF and turbo inlet, catted TBE, 08+ STI intercooler, and stock header/UP. For the boost tables, my target boost is the heavier red line. For AFR I have an Innovate LC-1. Anyway, screen shots of the results are below.
Boost for AVCS values 0, 5, 10, and 15
Boost for AVCS values 20, 25, 30, 35, and 40
MAF for AVCS values 0, 5, 10, and 15
MAF for AVCS values 20, 25, 30, 35, and 40
AFR for 0, 10, 20, 30, and 40
Although boost was higher with more AVCS in the upper RPM range, MAF readings showed the same or less airflow. So although 0 AVCS had the lowest boost, it also had essentially the "best" airflow since it was the same as 5, 10, and 15 but boost was lower. For my setup, aside from AVCS at 0 and 5, spool was the same. Part of that is going to be due to my boost targets for spool-up. I have a different boost target than Cobb in the spool-up region (2200-3300RPM). If you compare them to Cobb's OTS stage 2, I hit 17# at ~3300RPM and Cobb hits 17# at ~3200RPM but the ramp up to 17# is different.
AFR's were identical for every run.