Manufacturer implementation varied significantly, with some cameras not decreasing at all from Baseline to Main but dropping significantly when changed to High profile, while others actually increased when moving up profiles.
Differences between main and high profile in low motion scenes varied widely from a decrease of about 50% to an increase of about 30%.
In a high motion low light scene, switching from main to high profile resulted in differences which varied from reductions of 25% to increases of 25%.