are you using polar mount \ actuator ? is your pole dead straight.
i recently swapped and moved my dish, swapped my old 2inch pole for a 3 inch pole and have ditched USALS \ Diseq motor - to an H-H 36v motor, i paid special attention to pole when installing my CM - making sure it was dead level, the result, my arc has never been so good, around 16-17db on 30w and 45e - even on old setup with USALS, i never got that...even 53e at 14db atm.
that DB reading is from an Octagon SF8008 - i actually think they "under read" the value - as when i briefly had a TM5402 M3 - the readings were usually 1db higher on the TM, than the Octagon. Not sure which STB is to be believed, lower or higher reading.