Amended F11 for unclaimed tax credit

Hi

We have recently been given additional tax credits which means I have had to amend my previous income tax returns (form 11). As previous tax years are fully paid, I expected to get a refund for the full tax credit amount each year.

However, according to the revised return, we are only due a refund for the tax credit amount minus the tax payable for that year (fully paid in all instances). So for simplicity sake let’s say our additional tax credit is €1000, then as far as we were concerned in 2019 the allocation of the new credit means we overpaid tax by €1000 on the revised return and that’s what we would be refunded.

However for that year, we had a tax liability of €600, which was paid at the time. The now amended form 11 is telling us we overpaid by only €400, as it is subtracting the €600 liability and payment we made at the time.

There could be a very simple explanation for this, but I just can’t see it.... can someone explain this to me? As at this stage it feels that we are paying the 2019 tax liability twice

Thanks