You should have IU but you probably need a private doctor to evaluate you and your SMR's and VA medical records and say that you cannot work due solely to your SC conditionss. I know people who have much weaker claims than you, but they got medical opinions to rebut what the VA said every time they were low balled or denied. They won their claims just due to persistence and getting new evidence in the form of medical reports. You could even apply for voc rehab and if they turn you down, which they probably will, use that as evidence of IU. Voc rehab does not communicate with the VBA. When you ask for your C-File you won't get your voc rehab documents.