Not necessarily, but the peak power depends on so much. I found near 20hp by changin fuel form BP ultimate to V power and then more going to tesco 99.
Also the general condition of your motor beforehand, the cat condition etc all have an effect. When you get to 325hp, 5% difference gets you to over 340!!
Also depending on what revs your 1.6bar is coming in at, it may be it tails off earlier later on, givign you more torque and less top end.
I think set up on rollers with some jiggery pokery, you should get near 350.
BTW, your result does not surprise me, i took them out in mine at APS when mine was having its DV problems and Ed reckoned yours felt identical to mine at the top end. Mine was making 327 at the time at jabba, and only found its full potential when we changed a few things.
Fuel was one, as the timing was getting pulled back, I also fitted a cooler thermostat and some copper cooler NGK plugs, (all to drag some heat out of the combustion chambers).
It helped but the boost was tailing off too quick and lag was bad when warm..after much head scratching Mike at jabba located the problem as the brand new bailey DV sticking at 85degrees c, wheter open, closed or part way, venting off boost as it did.
Put a brand new TT one on and it was cured, no dump whooshy noise, bu the beast was born and it flies now!
Speak to Ed at APS and ask about the stock style bosche valves, if they have one they could stick it o to try it.
They also have an Evo one in their cabinet that can I understand be fitted to the 18Ts , bigger and more responsive allegedly.
