How do you mean by this, is the IR almost near impossible to pass first time or something?
Nope, what I mean is that the theory is that the CPL is not much different to the PPL you just have to be better and you get a reasonable introduction to Instrument Flying. The IR on the other hand requires that you be comfortable with flying the aircraft straight and level and that you can handle it plus the radio and the navaids with very little loss of directional or vertical control. Your flying should be better by the time you have flown the CPL because you've had all the practice you can get. That said many fly the IR before the CPL because it can be cheaper if you pass in min time. I did PPL/CPL/FI long break as an FI IMC/MEIR that worked fine for me but I honestly don't think I'd have had a problem with IR before the CPL if I had gone to AFT for the whole lot
