Thanks Infinity,
Are you able to offer more detail on the differences in the pilot tubes? A few questions I'd be asking were I to be with the two planes:
Is the bore diameter the same in each? Is there an entry point chamfer in one and not the other? Is there an angle of incidence difference? Is there a difference in the direction changes for the air within the pilot tube?
The pitot tube should not be a path for the flow of air, but rather the entry point at which air pressure is measured without flow. Thus, I would not expect that the air path or bore diameter should make a difference.
I'll be interested in your observations...