I appreciate the idea that a helo or tilt rotor can "experience" vrs, or that it "occurs" at 30 or 40 knots, but let's define "experience" or "occurrence".
The data shows that the V-22 had nibbles (5 to 10% torque variability - the blue data points) at about 45 knots (at a speed equal to the downwash velocity). This is not VRS, it is the beginnings, where they wanted to stop the tests to avoid losing roll control. Note that the reds were at about .75 to .85 of the downwash speed, where the torque variability is 10% and the tests were aborted. This is not VRS, it is the first sign of it.
For a helicopter, with disk loadings about 1/4 that of the V22 (2 to 7 lbs per sq foot instead of 22 to 25 psf) the downwash speed is much less, and so the vrs forward (and downward) speed is much lower. In a Bell 206 you would have to slow to about 10 or 12 knots forward speed to experience real VRS, and could get some nibbles at 15 to 18 knots.
The written test question is simply wrong, fellows. The idea that 35 knot flight is close to VRS is another way of perpetuating the myth, and allowing misunderstanding and superstition to cloud the learning experience.
When I took my FAA Flight Instructor written, I refused to answer one question. It asserted that in a climb lift was greater than weight (the least-wrong multiple choice). I wrote a brief critique of the question, with an explanation of why, and I got credit for a correct answer.
I know the regulators in several countries. Good people, professional aviators and great instructors, but they get their aero from the old piloting texts written by those who they follow. Few aero engineers dabble in the training publication world. A guy like Gordon Lieshman or Gareth Padfield could help square these publications away. Maybe I'll ask them to do so next time I communicate with them!
BTW let me congratulate the ppruners here, this is a great discourse, with erudite observations and sharp minds. I love it when someone posts something and someone else reads it, goes beyond it and makes us all actually think!!