Doug wrote:
I can tell you that I have been told to intercept the ILS at altitudes
well above the glideslope intercept altitude at the FAF by ATC. I have
been cleared for the approach outside of the FAF. I followed their
instructions and flew the approach. Never have had a problem. I don't
see what the problem is, so long as you are intercepting the glideslope
from below, and so long as you are at least as high as is charted you
should be. So long as you make sure you are at the proper altitude when
you cross the FAF, I don't see the problem. Unless I see it as unsafe
or some obvious violation, I do what ATC tells me to do.

The OP didn't say what ATC's instruction was, so we don't know. I don't think
ATC's instruction is relevant to the OP's question. The OP just wanted to know
whether descent to 1800 was mandatory. As far as we know, ATC didn't instruct
the OP one way or the other.

snip