Any turbulence in the flow has an influence on the measurement. An angle in front of the sensor will influence the measurement. By how much is difficult to say.
You can only correct this by comparing the sensor with a reference in your system.
Thank you for the reply.
So, I should probably install the sensor with a couple of centimetres of straight tubing in front and after, to get the most correct measurement.
With 5 out of 10 fittings being 90 degree already, I guess the flow will be drastically lowered.