Ashambles , inconsistent - not in this case anyway
The Lansdowne Road Agreement replaces the Haddington Road Agreement in the same way that the HRA replaced the Croke Park Agreement .
If agreed to by the various Union's memberships ( quite a big if , by the way ) the Agreement will run for three years from this year until 2018.
Over the course of the Agreement the vast majority of public sector workers will see their pay restored in 2 tranches - € 1,000 euros in both 2016 & 2017 - the State have based their calculations on these figures & given the fact that there are approx 280,000 Public Sector workers it is easy to see how the figures grosses out at 560,000,000 a large chunk of which will be recouped as detailed in other posts above.
Your calculation that any new Agreement will cost the State 2 billion euros is fanciful in the extreme.