[ncmncm]

OSL establishes a lower bound on age. Numerous events can lead it to read younger than the reality.

Yet, the Valley Temple and Menkaure pyramid come out 500 years older than the official numbers. (With wide error bars, it must be said.)

[AlotOfReading]

OSL can read both younger and older than the true age, depending on the error sources. Modern labs will usually apply a correction to deal with underestimation as well.

[ncmncm]

Maybe explain how OSL can establish an upper bound on age? It looks impossible to me, except where you can prove the sample was undisturbed.