125shifter

I have my boost control valve working with the parameters Simon at Motec gave me, but they need a little tweaking and I don't where to tweak. I'm trying to get the boost to hold steady at 1 bar boost or 200kPa. Here's a graph from a data log that shows how the boost spikes to about 210kPa and falls to 190kPa in less than a second.

My boost control settings are:
Aim boost 210kPa (I've set it high because at 200 it runs below 190kPa)
Normal position 40%
Trim 0
Air Temp Comp 0
Eng Temp Comp 0
Comp 1 0
Comp 2 0
Proportional Gain 0.75
Integral Gain 0.46
Derivative Gain 0.035
Min Duty 5
Max Duty 95
Positive Integral Clamp 10%
Negative Integral Clamp -10%

Any help is greatly appreciated .