If your going to keep it at std boost levels and like the boost to come smoothly, get an amal valve and pipe it up standard! If your not bothered then i'd guess at the actuator either A: being weak, as it peaks at 7psi, or B: it's been set up to peak at 7psi and it tails off a few psi (which doesnt neceserilly mean its broke) i'd set it up to peak about 9/10 and it should tail off to bout 7/8psi, would reccomend getting it set up by a pro though just incase it's not fueling properly.