Have you tried having a VRE counselor write a statement stating you are unemployable? Have you gone through VRE, if so, have you had an ILS assessment of your home from a VRE counselor? This would help your claim, IMHO, big time!
I was denied IU but once I had this statement from VRE stating that I was unemployable due to my SC condition, I was granted within a week. Literally, I read the denial on a Friday, called my VRE counselor that same day (in which he just left my house on the day of the denial), he wrote said letter, by the next Wednesday, he called and told me that I was granted IU! So for me it took said letter to be granted TDIU!
B6