Not sure about this, but if a injector builder has cheap injectors, it may be because he is using someone else's "Cores" for your set, and your set becomes someone else's set.....
It speeds up the delivery of the injectors to you, but you are not getting "Your" injectors back...they would be someone else's...
I am NOT 100% sure on this though...
Builders who start with reconditioned injectors from Ford will carry a way bigger price tag...just go price them out from ford to see...
Basically, all you are getting for your injectors is the core charge that the builder would get when they send your in as cores. (For the set they bought to make your aftermarket injectors with.)