That's most interesting, safetypee. So a consistent argument that would draw all the evidence together would be that:
For a standard 3deg GP:
a. The first false GP is at 6 deg, but
b. the first false one that gives logical demands is at 9deg
c. Falsies do appear at 12deg and upwards but may be discounted due to the extreme error needed to find them.
Anyone unhappy with that?
For the record I am therefore happier about intercepting from above (within reason), but still have a problem with the unclear wording in GASIL.