I have no first hand experience with this engine so my advice with this engine type comes from
other common rail engines that I have diagnosed.
It would have been nice with some sort of a log file either from the Launch scanner or even better from a picoscope diagnostic software, where the rail pressure sensor is being logged.
I have seen a description of the DTC P0087 where one of criteria to set the low pressure DTC are
a pressure drop below 140 bar in for 0,3 seconds.
With all respect for your measurement - I dont think you would see such a pressure drop with the
Launch scanner and this goes for any type of scanner you use. The time frame is to short, but it
might be possible to see with the picoscope connected to the rail pressure sensor.
I know, its not much of advise that I can give right now, but with a waveform capture of rail
pressure sensor it might be possible to diagnose your engine problems.