In the 2016 Season, Racers were no longer allowed to drop races. The 2017 Rule Book outlines a change to that rule, dependent on the number of races in the season.
SERIES FORMAT – Racers in the AMSA Off-road Championship will have the ability to drop races each season dependent on the number of races in the series.
6 Race Series – NONE
7-8 Race Series – ONE
9+ Race Series – TWO
The 2017 Rule Book is available here: http://allisonchampagne.com/AMSA/OFFROAD/rule-book/