I suspect that the low price on the auto-inject is simply because they are for older Macs and the demand is lower and slower.
I don't doubt your logic, trag, but that is certainly NOT the way it works on EBAY!
So again, it is curious to me that Shreve is pricing drives in just the OPPOSITE way that EBAY does. To me it indicates that Shreve is either an honest firm, pricing older stuff lower than the newer (as it should be in most cases), or they are deceptively hiding problems about the older equipment (very possible because older stuff is typically in worse shape than the new).