I believe what JamieKirby is talking about is the fact that it costs more to acquire item modifications to fill shells than it does to acquire similar stat crafted items:
But there are three things JamieKirby is not taking into account:
#1 - item modification items can be easily acquired with planetary commendations
#2 - the item modifications sold on the GTM are dominantly blue and purple quality and to get those schematics reverse engineering had to take place and a good portion of the value of those blue and purple quality items comes from that reverse engineering process.
#3 - shells and item modifications to fill them are always in high demand. High demand equates to more value. fixed stat crafted items are in less demand. lower demand equates to less value.
I am not exactly sure what your point was because you didn't state one.