Feeding Guidelines also arent definate amounts, each dog is different. I would feed him what he is used to and then gradually reduce it like Prin suggested.
A friend of mine has recently done the *crap food* to Evo as well and was having the same issue, her dog was always acting hungry. Its been about a month now and she has it all straightened out, but feeds a tad bit more than the "bag" recommends.
Courage is being scared to death and saddling up anyways. ~John Wayne