OK, I've done some basic figures - comes with a health warning, but it is in the ballpark. (I had 95% accuracy on KBC figures
)
Based on each 100k, taking average 27 years left on a mortgage at July 1st 2010.
Using an average charged rate of 3.5% for the period from July 1st to April 2020
Assuming a rate of 2.95% is charged for the remainder of the loan from April 2020 (this will change, but tracker rates will probably change at similar rates, so comparison should be valid)
The result is that the deal is the equivalent to a tracker rate of about 1.8%. If you had been getting the higher TRS relief, then its about 1.65%.
Average interest refund due on the 12% reduction is close to €4,000 per €100,000
Average reduction in Mortgage payments going forward based on current 2.95% rate is €50/100k/month.
An easy comparison is taking the total paid on a per 100k balance in 2010 @27yrs remaining @ av tracker of 1.9% (remember rates were not always 0%) is 128k
Total paid on 88k balance from 2010 @ 27 year remaining @ average rate of 3.1% for the full 27 years is €130k.
If you can switch to a 2.5% rate and can keep at circa 2.5% for next 17 years (a strong possibility), your total per 100k repayment will be 127k, and a circa 1.65% tracker.
And on top of this, you are free to switch without giving up any of the benefits of this deal
Considering many had given up on this, I think its an exceptional outcome.