[ttcbr600rr]

FICM rollback to VXCF4D3.
2005 F250 SCREW, 6.0, 373, 4" cat back, 325/65/18 BFG's, Gryphon.

Stock, no load, Hwy only @ 70MPH 16.9 MPG
Extreme, no load, Hwy only @ 70MPH 17.5 MPG
80 Hp DD, no load, Hwy only @ 70MPH 18.1 MPG
Economy, no load, Hwy only @ 70MPH 20.7 MPG @65MPH 20.9
Economy, no load, City only 17.1 MPG
80 Hp DD, no load, City only 13.8 MPG
80 Hp DD, 4800lbs, City only 13.4 MPG

Before FICM rollback
Stock, no load, Hwy only @70MPH 15.8 MPG
Tow, 5200lbs, Hwy only @ 64MPH 12.1 MPG
Economy, 5200lbs, City only 10.4 MPG
Economy, no load, City only 14.8 MPG
Tow, no load, City only 14.1 MPG

these are my findings, hope that anyone can use this for reference.

Thanks PHP