its not the fact its a ppl IR or CPL IR
the problem is if its a single engine IR or double engine IR
if you decide you dont want your CPL just yet you can get an ME and then your IR on your ppl. remember, the ME/ IR are ratings but the CPL is a new Licence
if you do it whis way i THINK the CPL reduces down to 15 hours instead of 25 but double check it.
might as well just do the ATPL exams that cover both the CPL and IR then do the CPL and IR after while the ATPL exam passes are still current.