I don't recall one instance when cleared descent to 9000' was confused with 5000' or vice versa. I think that FIFE and NINER are remnants of the past but I'm willing to accept that Jimal, you have witnessed it.
I'm a bit surprised that you Jimal, who appears to be a stickler for the rules, don't comprehend why saying things in the correct order and always starting off with.....''Bahrain control'' or for subsequent calls, ''control'' is so important.
The human brain comprehends things in a certain way. First off, ATC and pilots need to be clued-into a call and that happens by the first words used in a radio transmission. ''Bahrain control, Emirates123, FL390'' It is simple, concise and not prone to error. Or 'bahrain, emirates123 passing FL245 descending FL190'' Some pilot's don't even realize that ATC checks our altitude call and if not within certain parameters, they are supposed to question it.
It is critical for pilots to address the proper agency either by name or just ''control'' as the FIRST thing we say..........partly because it immediately advises all other aircraft on that frequency that the call is NOT FOR THEM! And since many aircraft flying around this airspace seem to have similar call signs, EK, EY,QR 501 or something close, so if we don't start off with properly addressing the controlling agency, many other pilots will starting thinking........ was that call for us to descend to FL 250? Or did AA501 just say, ''AA 501 descending FL 250''?
A pilot is either lazy or too stupid to know who they are talking to, if they don't start off each RT in the proper manner. First call to ATC for example, ''dubai ground, emirates 123...'' (subsequent calls can be either 'Dubai ground' or 'ground') It is the easiest method aside from being the safest but for some reason many pilots don't bother. I have to question, why?
I think it boils down to past experiences and improper training because if some pilots are consciously choosing to say things like...... Emiratie123 or This is the Emirates123, checkin in with you at two four oh............. then they shouldn't be flying planes.
Once again, I don't really care what the rules are as long as they are effective and even more importantly, they must be STANDARD.