The journey Dublin Pearse to Salthill & Monkstown does not seem right to me on the fares calculator - it's coming up with a €3.72 fare adult leap card fare.
Change the start to Connolly or the destination to Dun Laoghaire (which extend the journey) and it's €2.50.
http://www.irishrail.ie/rail-fares-a...arescalculator