The small diameter tubing that was used to convey the pressure information to the actual sensors introduced a phase lag [my italics] in the pitot-static system that eventually coupled into the Flight Control Computer... however, once the pitot tube pneumatic lines were increased in size, the pressure lags disappeared...
Keep in mind that was measuring "pressure". Pressure does change through out the tube. If the pressure was constant there would be no flow. However flow is uniform throughout the tube unless it is compressible, like air. The amount of flow entering the tubing at the needle must exactly equal the flow coming out of the tubing at the carb. If it doesn't, you either have air in the line or you will explode the tubing.
Wings