E85 tune on 2007

hi. i plan to upgrade my 2007 escalade to run with e85. first i use hptuner to modify internal program in the e38 ecm. activate flexfuel , copy values in all the flexfuel tables and spark tables , swap 30lbh injector to 54lbh flow rate. everything from the stock tune of a 2009 escalade. the only one question make me hesitate is that in the 2009 we have the FCPM module which is manage the fuel pressure and in the 2007 we don't have this module.
so does anyone know if fcpm is mandatory to fully activate the flexfuel mode ?