It all reminds me of a spat I had with the CAA after a medical, in which I had discussed my use of Ceterizine for hayfever (which makes some people, but not me, drowsy). My AME was happy with me taking it. However, as it was on the medical form, I then received a letter from a nurse at the CAA telling me Ceterizine was not allowed for flight crew, but not quoting any authority for this. I gave in - I wasn't up for the fight - and now use Loratadine, which means my hayfever is less well controlled and more of a flight safety risk. Ho hum.
There are definitely people in the CAA* who wish the regulations said something they don't, and so give their opinions as if they were facts.
*not just the CAA, I have the same problem with other organisations I deal with.