More than likely he's just running the BMS flash and not 100% e85. The added fueling from the flash takes care of trims and a few other things, but with 100% e85 you would run into LPFP not being able to maintain the volume required to support the HPFP after shifts.
FFTEC just posted a picture of the LPFP booster on facebook "Vishnu Performance Systems". I'm running this pump and have been for the past 3 weeks. I run 100% e85 with no LPFP codes. I was skeptical at first, but I was trapping 150+ at Shift S3ctor and didn't have any fueling issues running 100% e85.
BUT.... Regardless of what tune you're running, your DME fueling tables need to be updated to take advantage of this. Otherwise you'll still be maxing your trims.