The handicap of the FI

Something is wrong with the fog index calculation formula.

FI = 0.4*((WPS) + 100*(N_C/N))

(FI, fog index; WPS, words per sentence; N_C, no. of complex words; N, total no. of words)

It denotes the number of years of formal English education (FEE) required to understand a particular text. Readers' Digest articles have an FI of 12 while texts that require near-universal understanding have an FI of 8 (to give you a picture).

How is it that a person with only 16 years of FEE as I can write with an FI reaching 60? In other words, how does 16 years of FEE for a writer seem sufficient to necessitate 60 years of FEE for a reader?

The conclusion seems easy if the parameter of "formal English education" is omitted from the consideration because, if excluded, the quality of an academic background could be held as a nullifier.

The formula seems to have only a strong empirical backing, but nothing in the way of dimensional analysis—in a metaphysical sense—seems to indicate that the proffered combination of variables is equitable to #FEE.