Difference between EPS cables

[unreal_servers]

I've been working with some ICXes and EPSes lately, and had to order more EPS cables.

I found out that there is apparently a second style of cable connector.

All the ones I've had so far use a clip similar to how an ATX motherboard power cable is retained and they have a soft rubber hood around it to hold the cable jacket weave to the cable end.

The ones I received have a hard plastic hood, and a thumb screw.  none of my equipment has the mating threaded hole for the thumb screw.  Additionally, one of the 10 pins is "filled in" on both ends of the new cables to prevent them being used on my gear. 

BUT WHY?

What is so different about these two cables? 

Is there any difference other than the attachment mechanism?  (Ampacity, comms crossover?, thermal rating?)  I've been comparing pinouts via DMM and haven't found a difference yet.