I've started to read the paper more thoroughly, there is a reference [19] that explains the manufacturing indexes in more detail:
[19] O. Kerbrat, Méthodologie de conception d’outillages modulaires hybrides basée sur l’évaluation
quantitative de la complexité de fabrication, PhD Thesis, École Centrale de Nantes (2009) (in French)
This document can be found here: [
tel.archives-ouvertes.fr]
It's in french. My french is not too bad, I'll start reading through it after I've finished reading the paper.