Just out of interest, why would you want to add the CRI to an FI rating? As far as I understood it, there was nothing an FI couldn't do that a CRI could.
Might be wrong.
In my case, I wanted to be able to teach aerobatics to qualified pilots. I was unable to do this unsupervised as an FI(R) despite having the aerobatics instruction restriction removed. I found it difficult to get a willing supervisor because none of the supervising instructors at the school where I did most of my work knew anything about aerobatics. It was frustrating.
Being a restricted instructor also means you can't fly the SEP "one hour with an instructor" for your fellow group members or mates unless you can pursued someone to supervise you while you do it.