It's interesting. I took a similar test when I participated in some research into the vision problems for diabetics. Although, as usual my vision is worsening as I age, at least I can say I have perfect color acuity! (for what that's worth!)
A fun little test to take in a spare few minutes which is simple but desperately nerve wrecking as you begin to doubt whether this colour is lighter or darker than that one or whether this colour it more or less purple than that!
This is a really interesting test to take. I have what's called a red/green deficiency, so I was surprised I scored as well as I did- a 24. My mistakes were, in fact, at a couple of specific frequencies of red & green transitions.