The original MMPI was standardized on a group that, by todays standards, would be considered to be poorly educated.
There were also additional differences including no or few ethnic groups, relatively lower endorsement of "unusual" item content. and the impact of considerable social changes over the past six decades.
The result was that social class, in particular, had to be taken into account when interpreting the original MMPI since it seemed to influence Scales L, F, K, and 5 quite extensively.
However, the MMPI-2' s more representative sample means that, for most educational levels, education does not need to be taken into account.
However, for persons with quite low educational levels (less than 11 years), K and 5 (Mf) may have lower overall scores so that they need to be interpreted with caution.