Interesting. My first thought, is that you are a tint mistaken. But I could be wrong and have never looked closer at it. I know like other areas, you can enter a value, or you can slide to a value. But I’ve never noticed that they produce two different results of that color (in the color window). I’ll check that out.
When you think about it, the processes are the same (for what you are saying about tinting) as well as decreasing the opacity (in the color window). But to your point, I refer to decreasing the value (entered manually) as decreasing the opacity. You are taking a color and decreasing the content (via the color window). But doing that adds white, so in that sense, you would correct. Decreasing “opacity” is only done in the other window where you are doing the same thing as “making it transparent”. Adjusting the slider, or enter there manually also. You decrease the value for both, and you do that by entering numerically or by adjusting the slider (for both).
How do you “tint” a color? You add white to tint it. Tinting l(gets lighter). Shading a color, is to add black to a color. Tints and shades.