callsign should NOT come at the end
checking the AIM gives countless examples like:
American 623Heavy, fly heading 260.
not
fly heading 260, American 623 heavy.
ATC has to wait for the call sign all the way to the end...nope
the AIM for the USA is available as a PDF on the internet for free...I'm sure it is very close to the ICAO standards, with the only difference being: we say POINT instead of DECIMAL...and a few others