How does concealment stack?

[jmt11190]

How does concealment stack? Say for example, darkness, obscuring mist, displacement, blur, blink, and fog cloud, are all cast on one person (I have no idea why a caster would waste so many spells, but bear with me) and the attacker is standing next to the person to ignore the total concealment part. How does the concealment work, because it can't be total concealment, since it is still possible to see the person (although it is very hard). Is it added, the percent multiplied, or something else?

[Jack Mann]

Concealment doesn't stack, it overlaps. Just roll for the highest miss chance you're getting.

However, if you have a miss chance from a source other than concealment, then an attacker must roll for both.