The cons to a PCP deal are not in the cost of financing. Your comparison is not comparing two comparable scenarios. Ceist Beag has described why that isn't the case above.
There are a few cons to PCPs, which are mostly based around people either not fully understanding their commitments to the deal or simply overstretching themselves financially, but seeing as this is a finance website, from a pure mathematical analysis point of view, the low credit rate or 0% credit some dealers offer, PCP's will always work out cheaper than an alternative means of financing with a higher interest rate. You can't argue with the maths.
Correct and Ceist Beag's workings in #206 above using my numbers from Joe Duffy and PTSB also shows the PCP method to be more expensive.