Both cards would be due the €5 reduction.
PTSB took €5 3/01/2017
UB took €1.32 4/01/2017
I know the duty is calculated in a different way but still capped at €5 for dual usage card, so
why are the amounts deducted not at least the same.
Are you sure you didn't only make 11 ATM transactions with the UB card, and more than 41 with the PTSB card? The charge is 12c per transaction I believe, and capped at €5.