purlin trusses at 96 oc or tcbrg trusses at 32 oc
 

purlin trusses at 96" o/c or tcbrg trusses at 32" o/c
most of the industrial and big box buildings going up are using wood or steel purlin trusses spaced 96" o/c.
an argument can be made for a top chord bearing 2x4 truss system spaced 32" o/c is more economical. considering the hw hangers and 2x4 stiffeners are eliminated. most framers prefer the 32" o/c option, thus labor should be cheaper. and most if not all truss fabricators can provide a 32" o/c system where the 96" o/c system is significantly limited to fabricators who specialize in purlin trusses and therefore can gouge there prices.
i don't see the advantages to using a panelized system over a 32" o/c system or even 24" o/c. the trades should be able to work with both.
what am i missing ? what are the structural advantages with a panelized roof versus 32" or 24" o/c ?
thanks