http://atptrucks.com/ Check out the EFI live links he has. Probably one of the top 2 or 3 programmers in the country.
You can get economy tunes. H.P. Tunes, light tow tune, heavy tow tunes etc. Usually high h.p. tunes are the more fuel efficient tunes. They are built to be tranny safe. Also when switching tunes its usually best to run it for awhile so the Allison tranny can relearn and adjust for it.