Others may have an opinion, but I'll take a poke since you posted this in my forum...
-There can be a difference between OCC and UPOCC.
-The NC-06612 has brass contacts.
-The cost of the NC-06613 is more than 3.5 times the cost of the NC-06612.
If the NC-06613 is anywhere near your budget, I think a deal might be had. They were superseded by the NEX-OCC GD. If interested email me at the address on our site