Normal color vision gives the best resolution (in terms of wavelength difference percieved) in the yellow region. To most people 550 nm is definitely 'green' and 620 is definitely 'red'. The whole red-orange-yellow-lime-green transistion is only a bit over 50 nm wide.
I wouldn't be surprised if a strong NIR line would have a different effect on your color perception - perhaps your vision is just less overwhelmed by the green than most peoples.