Not sure why I am wrong. Avoiding significant altitudes is sensible but the difference between 500 ft and 2000 ft is negligible in terms of the partial pressure in the blood and so the amount of nitrogen that comes out of solution.
The partial pressure at sea level is 760 mm Hg and falls by 23 mm Hg per 1000 feet. This makes no difference. When we use a hyperbaric chamber in flight we pressurise to 1.5or 2 atmospheres ie an additional 760 mm Hg and we go up to 3 or more atmospheres when using hyperbaric therapy for other diseases
So flying at 2000 makes an academic but not a physiological difference and flying below normal rotary altitudes cannot be justified on flight safety grounds. Avoiding flying over a 10000 foot mountain is obviously a good idea
But heck I am just a doctor