An honest professional will freely admit that they don't know the answer to a particular question if that is indeed the case.
If their honesty disappoints, so be it.
The tax code is littered with provisions that often necessitate specialist study by a suitably knowledgeable specialist in order to gauge their applicability or otherwise in a given situation.
I've seen in a few posts that when selling a house that was a PPR for some period of the time, that the CGT is not applied on the PPR period + 12 months.....
However when I looked that this calculator it does not seem to add on the '12 months' to time as PPR when it does the CGT calculation
Its looks like there is another way to look at this.
Calculating the gain BY applying PPR relief to provide an amended gain,
Then applying S604 A on this amended gain, the balance thereafter (after the deduction of €1,270) to be charged to CGT.