I am sorry to say that ...
It not because the FCC delay it due Sorenson isn't ready...
You just need to understand how VRS number work and how that netural work.
The Neustar have VLog about what default VRS mean and it explain very clarify as same Sorenson. I have seen Purple and ZVRS explain what default provider mean.
What it seems be missing all VRS try to avoid the 'technical' stuff that customer may overwhelm with term "MAC ID" or "Physical Address" to run on one number not muilt different number for one machine. It seems the FCC goal want that IP Address become not our issue anymore such as hassel deal with firewall issue.
It similar with cellular phone has phsycial address on each device that run on IP Address while we don't have to deal with it.
I think that great deal and challenge our VRS can prepare for realized to real world. I believe that hearing people will have videophone like rest of us and it may be BIG deal to VRS provider who design their own product such as MVP or VPAD or the VP200 and those are big chance for Hearing people can have those with quality device and again ten digit number too.
if you want proof source about Neustar's VLog, just let me know and will link that to Neustar VLog website
Life is giving to us, we earn it by giving it. Let the dead have the immortality of fame, but the living the immortality of love - mean next child earn the life from me, because I love my child that mean lot to me will give to next little person earn the immortality of love from families.