TERPS 8260.3D Chapter 14. Departure Routes, 14-3-4 . Construct turning segments when the course change is more than 15 degrees
Whereas in PBN manual, it seems that a deviation of 10 degrees is considered a turn.
PBN 8260.58A 1-2-5,b,(1)a . [...] Not applicable for FB turns of 10 degrees or less.
Am I missing something. Is there any consistent rule that states when a transition between legs of an Instrument Procedure is considered a turn or a straight flight?