The tails are usually represented by a very tiny number of actual persons in the standardization sample (typically about 100 samples go into each age bracket). So yes, the real number at an extreme right-hand tail position may be quite different from the theoretical distribution.

The left hand tail is also overrepresented, likely owing to the many ways that cognitive development can be disrupted. And both tails appear to be especially overrepresented among males.
_________________________
...pronounced like the long vowel and first letter of the alphabet...