from the us? i must be missing the question.
even though some certificates can be used with qualcomm or exynos based devices of the same device family
us phone - us cert
overseas phone - overseas cert
the cert is simply some AT cmd,the problem everyone has is they cannot sign them, but they are simple to make.
like i said this service can be used with your imei or mine, however all imei cannot be signed and will take about 48 hours if you choose to supply your own imei, or i have some certs ready to go now if you choose to use mine.
if you use my imei the imei/cert will only be sold one time so you are the only owner.