50 and 950 make sense because of the way human perceive colors. We perceive colors in a quadratic way. This is why sRGB has a gamma curve, among many things. It

50 and 950 make sense because of the way human perceive colors. We perceive colors in a quadratic way. This is why sRGB has a gamma curve, among many things. It means that the difference between 500 and 550 wouldn’t be as relevant as the difference between 0 and 50