Seems to me the difference between CPL+IR and ATPL is purely your level of flying experience -- not a measure of qualifications.
For clarity, when I said you convert CPL+IR to ATPL when you have
enough PIC, multi-engine multi-crew time (etc etc)
I meant experience exactly as you describe: experience on multi-crew type, PIC, x-country, night, instrument, and so on.
As I understand it, when you have a CPL+IR, but lack the requisite flying experience, THAT is when you are deemed to hold an fATPL.