There is a (minor) flaw with the current computation method of fair scores. The current method is:

Fair Score = USGA Differential - USGA Handicap Index

While the differential score includes ESC scores, tossing out "blow-out" holes, I think the fair score of a given golfer on a given course, on a given day, should not use ESC scores: the actual score should be used instead, IMHO.

The purpose of not including blow-up holes is to not artificially inflate handicap indexes (and thus gain unfair advantages in competition). However, in head-to-head scoring (which is what Fair Score purports to do), the actual score, adjusted for handicap if necessary, is the score, unless special rules are agreed upon (eg mulligans, etc...).