Thanks for clarifying
@Sophrosyne.
This top slicing episode was the only time I had direct dealings with Revenue. I had to explain the rules to them.
The first TSR joint calculation was done wrong and was in my favour to a reasonable amount.
However it was about 15k less than the optimum single calculation. When Revenue then calculated the single assessment they again miscalculated and were leaving me short by about 2k.
I disputed this and they did a second single assessment and this was still short by a few hundred euro.
I finally printed out my last 3 years tax returns and did my own TSR calculation. I sent these to Revenue suggesting that this was correct. They accepted my calculations.
Revenue officials were incapable of doing a simple addition of 3 years total earnings and 3 years tax totals and working out the correct average tax percentage.
They also did not know the rules of how TSR should apply to a married person.
They also sent hand addressed replies on two occasions both of which had errors in my address. I was impressed with an Post. They managed to figure out the correct address on both occasions.
The official on the phone was well mannered and thanked me for enlightening him.
I have all this correspondence and if Revenue ever pull me up for making a mistake I will throw this back at them.
Revenue could do with having some people of your expertise.