3.1 Measure Angle > 120 degrees

Try to mount your sensor perpendicular to your machine. Especially at large plate angles like 120 - 180 degrees (flat plate), the die reflected the laser line to the plate (also the other way around) and you get a double laser line, if the sensor is not mounted perpendicular. This more or less close double line biased the result angle.

Put a mirror on the die and check, if you have a double laser line on the die. Try to improve the sensor mounting so that the reflected line is on identical position as the original line.

If the bend angle is smaller than 120 degrees this effect becomes less important, as the reflection is not that strong any more.